Fall Hours

9:00am to 6:00pm Daily

5050 SE Stark, 503-231-5050

9000 SE Division, 503-788-9000

Portland, OR

  • facebook48
  • twitter48
  • news48
Portland Nursery

FAQ Archive

Our Newsletter Subscribers have free access to our email question and answer service. In our FAQ Archive, you can read some of the past questions sent in. To have your gardening questions answered from our information desk directly to your email, sign up for our newsletter and get a coupon for 25% off pottery in the deal!

 

 

 

 

 

 

“What should I know about protecting my tender or cold sensitive vegetable and herb starts in this fluctuating spring weather?” May 25 , 2009

Several common vegetable and herb plants, including tomatoes, peppers, eggplants, basil, squash, cucumbers and melons need consistent warm temperatures to perform well. Many people like to plant such warm season plants the first sunny weekend in April or May, but sometimes extra protection is needed against night chills or poor weather that follows. Tomatoes, peppers, and eggplants will do best when they do not experience temperatures below 50 deg F, including night temperatures.

For this reason, they do best with some protection in April and early May, possibly with red plastic mulch, season starters (plastic sheeting that holds water, forming a temperature buffer), or inside a greenhouse or bright spot in the house. Basil is especially fussy about night temperatures, so keep it protected until nights are consistently in the mid-50’s deg F. With squash and their relatives, as well as melons and corn, it is best to wait until well into May before placing them in the garden.

BACK TO TOP


“Your perennial tables are full, but the summer blooming plants I am looking for are not represented well. What am I missing?”

Many of the later bloomers become more readily available closer to when they bloom. These include Shasta Daisies, Coneflowers, Black-eyed Susan and Asters, among others. In some cases the plants do not look very good early in the growing season, and in others the demand for things not yet blooming is low. Some also need higher temperatures to really get growing, and break dormancy later in the spring than other perennials. Rest assured ,we will have many such plants available in the coming weeks.

BACK TO TOP


“Several of my evergreens, especially my Phormium (New Zealand Flax), Hebes, and Rosemary, took extensive damage during winter storms this year. Will they come back? Should I replant?”

Some evergreens, such as those listed, suffer tissue damage under extreme winter conditions. Sometimes the plant dies, and sometimes the leaves and stems are ruined but grow back the following spring and summer. In the case of Hebe and Rosemary, we have seen some that seem to be growing back, and some that appear truly dead. Most (if not all) of the Phormium seems to be alive at the root level, and may grow back in warm weather, but it will take awhile.

Whether to replant with the same or replace with something else is a personal choice. It is possible to replace your plant and have the replacement do well for many years, but if we have another bad storm during the following winter you could lose the replacement plants. We have viable, and in some cases large, replacement plants available for sale.

BACK TO TOP


“I am seeing lots of blooming dogwood trees around town. If I decide to get one, what should I know about the different types?”

There are a few different species of dogwood available in the nursery trade, as well as some new exciting hybrids. The two most common species are Cornus florida (Eastern Dogwood) and Cornus kousa (Korean Dogwood), with different colors and cultivars available. Simply put, the Eastern Dogwood blooms before the leaves are fully developed, creating an impressive spray of color. They are susceptible to some leaf diseases, though, that in some cases can be problematic, with regular spraying necessary. The Korean Dogwoods are much more disease resistant, though some do not think them as impressive to behold, as the leaves emerge first, then the flowers. Some hybrids (check out the Rutger’s Hybrids) combine the best of both worlds. See our feature on Cornus to see our detailed page on available dogwoods.

BACK TO TOP


“What is this insect, and what should I do about it?”May 25, 2009

The warmer weather is bringing the insect pests out in force, and here I will highlight a couple of them that are really popping up now. AphidAphids are very common this time of year, appearing on many different plants, including several types of vegetables (common on brassicas, especially), roses, lupines and many other perennials. They are soft bodied insects that feed on the new growth and buds of plants, and they come in many colors, often green or black. They can leave a sticky, clear residue on your plants, and are often accompanied by ants, who farm the aphids.

They can be controlled by a number of different insecticides- the problem is not that they are hard to kill; it is that they breed and come back so quickly. Alternately, ladybugs (or lady beetles) Aphidare a natural predator and, when released in the area, will keep the population of aphids fairly low. Note that insecticides will generally kill ladybugs too, so insecticides should only be used before releasing ladybugs.

Another common insect this time of year is the first emergence of the spittlebug. Spittlebugs are named because they make a Spittle Bugfoam-like substance to cover their bodies- they look like somebody spit on your plant, usually at a leaf joint. Despite the fact that they are disconcerting to look at, they are not very destructive to plants, even food crops. SpittlebugUsually a blast from the hose will send them flying. If you should feel the need for insecticides, neem oil can help control them (Again, this is generally unnecessary).

BACK TO TOP


“We are starting new raised vegetable beds in our garden this year. What should I be using to make them and what should I fill them with?”

Any untreated wood (avoid pressure treated wood) can be used to make beds, though cedar and redwood are the more rot-resistant options. We sell kits, made from recycled plastic, to easily make a small bed. As to filling the bed, our best recommendation is a new bagged soil product we are selling called Gardener’s Choice Planting Mix, made especially for this use. Potting soils are also acceptable. If you wish to use clay soil or existing fill dirt on your property to save some money, we do encourage you to amend it with a fair amount of compost, and possible some pumice to increase drainage.

BACK TO TOP


“When planting blueberries, what amendments should I be using and what should I be fertilizing with?” May 20, 2009

First of all, blueberries prefer a site that can be kept moderately to evenly moist, but it is best to avoid a place where water stands. They require a pH that is much lower than the average garden plant desires, and amending is generally based on this need. Plant with some acidic planting compost, such as Azalea, Camellia and Gardenia Mix or Black Forest planting mix.

Peat moss is also sometimes used for this purpose. We do not recommend using aluminum sulfate as an acidifier for blueberries. To fertilize them, use a plant food labeled as appropriate for Rhododendrons, or use Holly-Tone by Espoma.

BACK TO TOP


“I’m interested in the very bright yellow and orange azaleas I am seeing just coming into bloom. What should I know about them?” May 20,2009

This is a reference to the deciduous azaleas, some of the largest growing and brightest flowering of the azaleas. It includes several species and, more commonly, groups of hybrids. These include exbury azaleas, azalea mollis, and many cultivars, including ‘Golden Lights’, shown below.

Azalea 'Golden Lights'These azaleas are great in the spring when they are in bloom, though they are susceptible to powdery mildew later in the season. The mildew does not kill your plant, but it does damage the leaves. Some of our staff recommends co-planting with large herbaceous plants that are showy in the summer, such as maiden grass or Cannas, so that these can steal the spotlight later in the season.

Deciduous azaleas grow best in at least moderately draining soil that is acidic. They can grow in sun or shade, avoid either excess reflected heat or deep shade.

BACK TO TOP


“You seem to be out of the vegetables and bedding plants that I’m looking for early in the week, especially on Mondays. What am I missing?” May 20, 2009

We receive our weekly deliveries of color and bedding plants during the week, and we are busiest selling during the weekend. Sometimes late on Sunday and on Monday there are gaps in our stock. The best days to shop for full availability are Thursdays and Fridays. We are open until 7:00 PM most days, and stay open late until 8:00 PM on Fridays and Saturdays (during spring and early summer only) for after-work shopping.

BACK TO TOP


“What things should I know about planting and growing my tomatoes?” May 20, 2009

Ah, the tomato, probably the most popular of the home grown vegetables. Here are a few tips to help you succeed.

When actually planting the tomato start, strip some of the lower leaves from the plant and lay the start down on the soil, nestling some of your amended garden soil around the vine. Yes, lay it down. The plant roots from the buds that the former leaves were growing from, and more roots mean a faster start for the rest of the plant.

Provide your tomatoes with enough calcium. This can be done by adding lime to the planting hole, also bone meal provides some. Our hardgoods department manager actually recommends hydrated lime or calcium flower sprays (we have all of these things) because these tend to work quicker than dolomite lime, the more traditional option.

Also, click here for our Tomato Tips Pamphlet.

BACK TO TOP


“My roses are starting to develop disease, with black splotching on the leaves. What to do?” June 1, 2009

AphidThis one is familiar to most experienced rose growers. It is one of several diseases that affect roses, and is usually called black spot (Diplocarpon rosae). As shown above, the leaves develop black blotches and the surrounding tissue turns yellow. The disease can cause significant defoliation and reduces the vigor of the plants, and can eventually kill them.

Cultural treatment is your best defense for this. This means picking infected leaves off the plant, removing fallen, infected matter under the plant, providing adequate air circulation and plenty of direct sunlight, and keeping the leaves dry when watering the plant. Overhead sprinklers are a big ‘no-no’ with roses.

Try spreading the frequency of watering out as far as possible between deep soakings. Also, be careful of companion plants requiring more water than roses like. Some roses are more susceptible to disease than others, with wild and shrub roses showing much better resistance than most floral hybrids (hybrid teas, grandifloras, etc.).

Fungicidal sprays can also be used to help control the spread of this disease, but do not kill it off entirely. We sell several sprays that can help, including copper soap, flowable sulfur (don’t confuse these two with the dormant sprays) and Fung-onil.

BACK TO TOP


“Do you have sunflower starts or seeds to grow the edible sunflowers?” June 1, 2009

Sunflowers are hot weather plants and are ready for sale as a plant later than most annuals. We do not yet have a large stock of started plants. We will, as we get into June have an increasing supply of them, definitely in ornamental types and likely in edible types. Our seed buyer will be trying to restock on edible varieties in seed for sale soon. Varieties to look for include Mammoth, Greystripe, Paul Bunyan, and some others that are the large, yellow flowering cultivars.

BACK TO TOP


“It's not raining anymore and I am thinking about irrigation; what methods and items do you have and what should I know?” June 1, 2009

We carry hoses, hose-end sprinklers, soaker hoses (these leach water through a hose all along the hose), tree watering bags, and the Acu-Drip drip irrigation systems. The soaker hoses and drip irrigation can save you time over the long term. Drip irrigation takes some initial installation time, but can last quite long and is versatile in the ways it can be used.

One thing to understand about sprinkling style systems of any kind is that they generally get the top layer of soil moistened, but this is not necessarily the best way to be watering trees and shrubs that you are trying to get established.

Frequent, top-layer watering encourages shallow rooting and, in the long term, trees and shrubs are better off with a deeper root system. This is best done with a long soaking from a hose or with the tree watering bags. You can encourage this by watering more deeply and less often. Of course, when in a mixed planting with annuals or other small plants, you do need to keep those plants hydrated as well.

BACK TO TOP


“There are holes in the leaves of my garden plants, vegetables and perennials mainly. Is this slug damage? I did treat for slugs.” June 1, 2009

Overall, there are a number of insect pests that chew leaves, but slugs are the main culprit, especially for lower garden plants (caterpillars are the main culprit for trees and shrubs). This is a good time to rehash the subject of slug control. Slugs are pretty much everywhere in the Willamette Valley, and a few weeks of somewhat warm temperatures means that they have been breeding. So, as to control options.

Baits are the number one method used for slug control. They are granules which contain slug poison that you lay down near infested or susceptible plants. The slugs are attracted to it, eat it, and die. Fairly simple, and effective. There has been sufficient research done to show that baits are more effective than any sprays at controlling slugs.

Traditional baits contain metaldehyde, and are cost effective but unfortunately are poisonous to dogs, who sometimes eat baits. Dogs have been known to die from this. The product Sluggo, which we also sell, contains Iron Phosphate and is not nearly as poisonous. It is more expensive than traditional baits, however.

We also sell copper strips, which by some curiosity of nature slugs cannot cross. These are especially effective for a raised bed where they can be stapled to the outside of the box, preventing new slugs from entering. On the soil, they must be kept clean to be effective, and this can be a tedious chore over time.

Beer traps. yah, slugs like beer. More precisely, if you sink bowls into the earth so the lip is even with the earth and fill them with (cheap) beer in the evening, slugs will be attracted by the smell, will climb in, and drown. Moderately effective, unpleasant to clean out. Also, some gardeners that are really upset will go out in the middle of the night with a pair of scissors and a flashlight and, well, take out their aggression on the slugs. Probably a good plan if you are literally losing sleep over slug damage.

BACK TO TOP


“The leaves on my roses and some perennials are marked with weird, orange, fuzzy spots. What is this and what is to be done?” June 15, 2009

http://www.plantpath.wisc.edu/PDDCEducation/mastergardener/images/Slide012.jpgAnother of those leaf diseases that rose growers are familiar with is popping up its head now. Commonly called rust, there are a number of diseases that all look similar and have similar consequences. Rose rust (Phragmidium sp.) is common and pictured below, and many perennials in the mallow family (especially hollyhock, but also Mallow and Lavatera) get the undersides of the leaves affected by their version of this disease (Puccinia malvacearum).

These diseases can cover leaves and drain the plant’s energy, and can cause leaf loss when heavily infected. Fungicides such as Immunox and  sulfur can lessen the damage, and it is a good cultural practice to remove heavily infested leaves and avoid wetting the leaves.

Rust on rose leaves.

BACK TO TOP


“What do you have in the way of hydrangeas, and can you give me tips for growing them?” June 15, 2009

We carry a pretty good selection of hydrangeas this time of year, as they are just coming into bloom. We carry selections from at least five species, including Hydrangea macrophylla (common Hydrangea), H. quercifolia (Oak leaf Hydrangea), H. paniculata (Conical blooming Hydrangea), and others.
Common Hydrangeas flower best on second year wood, so pruning late in the growing season or in the winter can lessen or even ruin the next year’s blooming. 

Some people recommend a three year pruning cycle, where any healthy stem less than three years old is left completely alone, and any that are that old are removed entirely, to be replaced with the younger shoots. Note that some newer varieties seem to bloom quite well on new growth/pruned wood. These include ‘Endless Summer’, ‘Blushing Bride’, ‘Penny Mac. ‘Nikko Blue’ has been reported in some trials to partially exhibit this trait as well.

Most hydrangeas should be grown in some afternoon shade, though the Oak Leaf Hydrangea can stand quite a bit of sun. They like moderately moist (not soggy) soil, and damage quickly if allowed to fully dry. Feeding somewhat generously when they are actively growing can increase the effect of the blossoming.

Read our feature on hydrangeas.

BACK TO TOP


“I get worms in my apples, and I want to prevent that this year. What can I do?” June 15, 2009

The ‘worms’ are the larvae of codling moths, or are apple maggots. Codling moths are more widespread, and affect a larger number of fruit types than the maggots. Codling moth damage is most commonly associated with an entry hole near the base of the apple and feeding towards the center of the fruit. The codling moths overwinter as larvae on or near the tree, and in spring they emerge as adults, usually just after the tree is finished blooming. Monitoring traps placed in trees can be useful to get an idea of the population level you might have, but are not in themselves highly effective control. Unfortunately, by this time of year (June) many larvae may already be in the fruit, and there is nothing to be done to save those fruits. Destroying them (and the larvae in them) may be your best bet.

The best time to spray pesticides (malathion is sometimes recommended for the home gardener) is several days after the tree is finished blooming, and you should continue to spray through spring and early summer at intervals. Put this on your calendar for next year if you have had these pests. Please be sure to follow guidelines given on the packaging of the insecticide you select, such instructions supersede any information given here.

The apple maggot is the larvae of a fly, of the same name. The damage caused by them is generally irregular, not following a set pattern. The maggots are similar in appearance to (but possibly smaller than) common maggots, such as those of the house fly. The flies are more active during hotter weather when compared with the codling moth, and it is or will soon be time to begin control. Hanging monitoring traps as soon as possible is recommended, and begin spraying when they are detected, or in July. Again, the insecticide malathion can be appropriate, or you can use pyrethrins.

BACK TO TOP


“It is veggie season, why don’t you have any peas for sale?” June 8, 2009

Peas are, simply put, a cool season crop. They grow best in moderate temperatures, with days under 80* F and nights below 65* F. We don’t sell peas this late in the season because we want you to succeed. Peas are susceptible to something called Pea Enation Mosaic Virus. This is a virus that is spread by aphids, usually in May in our neck of the woods.

Once the plant has Enation Mosaic, the fruit is often distorted and unacceptable. The best defense is not rigid control of aphids, but proper timing of your crop. Planting a pea crop in February or March usually means success (at least as far as the Enation Mosaic goes), while a planting in May or June usually yields a poor harvest. It is also possible to grow another crop in autumn.

BACK TO TOP


“What is with the chew marks on my plants?” June 8, 2009

I highlighted slug control a week ago, and now I will explain caterpillars and their damage. Caterpillars are the larvae (youth) of moths and butterflies. The adults are often pollinators and beautiful, but caterpillars can cause frustrating damage to our plants. They are the number one leaf chewing pest of trees and shrubs, and many kinds also attack annuals and vegetables. There are many, many types, but suffice it to say that if it looks like a ‘worm’ and is a leaf chewer, it is probably a caterpillar. With such a wide range of species, they can occur at many different times of year, and some types have multiple generations per year.

Small populations can often be controlled by hand (caterpillars usually don’t leave their host plant), and larger or harder to control infestations by spraying. We sell and recommend  the products called ‘Caterpillar Killer’ or ‘Thuricide’, both of which contain the bacteria Bacillus thurigiensis var Kurstaki. This bacteria is quite lethal to caterpillars and some other juvenile insects, but there is little risk of harm to humans when the product is used correctly. These products do not necessarily work for a broad range of insects in general, so if you want something that will work on more than just caterpillars, a pyrethrin spray will also fit.

http://members.tripod.com/sactorose/insects/16leps/16tobaccobudworm2.jpgThe Geranium bud worm, a common caterpillar on geraniums and petunias.

http://www.pestproducts.com/images/tent-caterpillar-tent.jpgA nest of tent caterpillars, which usually strike en masse during the autumn.

BACK TO TOP


“What’s the scoop on bananas; are they hardy or not?” June 8, 2009

The majority of banana plants are tropical and are not hardy to our climate, meaning that they cannot survive our winters outside. That being said, most bananas make fine houseplants and can be grown year-round in a pot, brought in before the threat of frost. Often times they look nice even in the middle of winter, if given reasonably good care. All red-leaved bananas, which can be stunning, fall into this category.

There are two types of bananas that are hardy and can survive our winters. The Musa basjoo, or Japanese hardy banana, is the more common of the two. It is a true banana that can reach 15 feet tall, though it doesn’t always do so here. Even if the leaves and stalk of the plant die in winter weather, the root almost always survives (it is listed as hardy up to -20 deg F when mulched). Additionally, we have  Musella lasiocarpa, the Chinese Flowering Banana, which grows and impressive yellow bloom once reaching about five feet tall. It is a relative of Musa (fruiting banana).

All bananas enjoy moderately moist soil, plenty of sun when possible, and regular nitrogen during the growing season.

See our feature page on bananas.

BACK TO TOP


“What is that lovely grass?” June 8, 2009

Fountain GrassPennisetum setaceum ‘Rubrum’, the Purple Fountain Grass is the probably the darkest-leaved grass available, and is absolutely stunning in the summer. People have been growing this for many years, but still many gardeners don’t realize that it is not hardy in our climate and should be planted as an annual (unless you have a heated greenhouse for overwintering). Overall, it is easy to keep as an annual, preferring plenty of sun and at moderate water.

BACK TO TOP


“The newer leaves on my Azalea are distorted, bloated, and starting to get covered in a fine white powder. What's going on?” June 23, 2009

Azalea leaf gall, Exobasidium vaccinii, is a fungus that can affect azaleas in the way described above. It does seem to drain the plant’s energy and reduce flowering in following years. It is worst in humid, late spring weather and can seem to appear or disappear for a year depending on the weather. This disease can spread from nearby camellias, kalmia, huckleberries, as well as from other azaleas. The galls (as the bloated portions are called) turn hard and dark later in the summer.

Control is primarily removal of the galls before they turn white and powdery. Once they are, the spore (or seed) of the fungus will spread and it can come back worse the next year. Copper based fungicides can help to control if sprayed during and after bud break (March through May), though some forms of copper can damage evergreens such as azaleas. Copper soap is the safest of the copper products sold for fungus control.

BACK TO TOP


“I have heard rumors about a new lilac, one that reblooms after the initial flowers in spring. Do you have any?” June 23, 2009

No, alas. These are very new and we will probably not see any for sale for at least a year, possibly longer than that. Please understand that we will get some as soon as we can, but (oh,oh, forgive the pun) they do grow on trees, and that takes time.

BACK TO TOP


“The new growth on my apple tree is curly, and covered in a white film. It looks sickly. What is going on?” June 23, 2009

Powdery MildewHere is the infamous powdery mildew showing up again. It also strikes roses badly, as well as some perennials and annuals (lupine, begonia, monarda, etc.). Typical anti-fungal recommendations are to reduce water on leaves, and increase available sun and air flow.

Standard fungicide sprays (sulfur, copper, Immunox, etc.) can help keep it at bay, as well. It more commonly strikes the new growth of the plant.

Powdery mildew on apple branches.

BACK TO TOP


“My tomato is blossoming, but the blossoms are just falling off. What is going on, and how can I encourage fruit set?” June 29, 2009

Several people have called regarding this problem, even when the plant seems to be growing well and is blossoming acceptably. Two customers in a row spoke of it regarding their Brandywine tomatoes, even when other tomatoes are setting the fruit. A few things can cause this.

One of the primary factors is temperatures. During rapid temperature fluctuations, or when nights are too cold or days too hot, this can happen. There is little to be done about the temperatures, of course, and sometimes one must simply be patient for fairer weather.

Inconsistent watering can also cause this problem, and this is of course all about the gardener. Tomatoes should be thoroughly watered when you do so, and should not be allowed to dry to the point of dehydration (wilting, etc.), but it is good for the soil to partially dry between waterings, especially allowing the surface of the soil to dry before they are watered again.

Also, some references recommend that the gardener tap the flower (gently, with your finger) when it is open to spread pollen and help to insure pollination.

Download our brochure Tomato Growing Tips.

BACK TO TOP


“What plants can be used for privacy screening in a shadier spot?” June 29, 2009

Most traditional hedge plants prefer mostly sun, including arborvitae, laurels, and boxwoods. These may not die in a shadier spot, but they can be considerably thinner, and thus do not serve as a sufficient screen.

Some evergreens actually prefer some shade, particularly in the afternoon, and these include Aucuba japonica, Fatsia japonica, as well as Camellias, Kalmias, and Evergreen Azaleas. Also, Privets (Ligustrum) and Yew (Taxus) are sun preferring but tolerant of some shading. Fargesia species, a group of clumping bamboos, can tolerate some shading as well and are thick and bushy compared to other bamboos. Please note that any shrubs can end up being thinner when placed in deep shade.

You can also download our Shade Screen Plants brochure

BACK TO TOP


“My Euonymous looks sickly, what’s going on?” June 29, 2009

EuonymousI recently mentioned powdery mildew on apples and some other hosts, but this week we have seen many samples of Euonymous shrubs or hedges coming down with it. Euonymous are quite susceptible to the mildew, and it seems to be coming out in force now.

Many people keep their Euonymous trimmed as a tight hedge, and this can actually be a disadvantage for the plant. When they are thinned out, the mildew is generally not as bad. That said, if you are using it for privacy, sometimes this will simply not serve, as a thinned plant grants less privacy. The gardener needs to find the balance. Aside from this, standard anti-fungus measures should be observed; provide plentiful sun, avoid wetting the leaves, and of course spray with fungicides as needed.

Powdery mildew on Euonymous

BACK TO TOP


“My laurel seems like it is being eaten, with holes in the leaves. Is this an insect pest?” June 29, 2009

It is of course possible that laurels can be eaten by caterpillars, but most of the time little random holes in Laurel leaves is caused by a fungus, generally called shothole. It is named because the leaves look like they have been peppered by a pellet or shotgun. This can also be a problem with cherries and plums, which are relatives of laurels.

This damage is unsightly, but rarely affects the long-term health of these vigorous shrubs. As with powdery mildew, mostly sun and dry leaves helps. The damage generally ceases to affect new growth when the weather dries in the summer.

BACK TO TOP


“What shrubs can I plant that will bloom all summer?” July 6, 2009

There are several options for the flower enthusiast. These include Potentilla, Hebe, Roses, Buddleia (be aware that the classic Buddleia davidii can no longer be sold in Oregon), and Escallonia. Also, Lagerstromeia (Crape Myrtle), Cistus (Rock Rose) and Hibiscus syriacus (Rose of Sharon) bloom for quite a long while. With the exception of roses, I would classify all of these as fairly low maintenance plants, and Cistus and Potentilla are quite drought tolerant once established.

See our feature pages on Lagerstromeia and Roses

BACK TO TOP


“Why are the leaves of my tomato plant curling up?” July 6, 2009

Leaves rolling up on a tomato can be caused by a few different causes. Some are diseases, but the most common cause is cultural. Inconsistent watering, especially overwatering, can cause leaf roll.

Fluctuating temperatures can also play a part in this. Remember to water your tomatoes moderately; giving them a good drink when you do, but allowing them to partially (not fully) dry between waterings. Aside from this, there are a few diseases that can cause rolled leaves.

Fusarium Wilt and Bacterial Canker can both cause curling, but are generally accompanied by failing/yellowing leaves, sometimes one only one side of the plant. Curly Top, a viral disease, can cause curling of leaves (obviously), but is generally accompanied by tough, leathery tissues with marked purple veining on the leaves. If these other symptoms are not present, the problem is usually cultural.

Download our brochure Tomato Growing Tips.

BACK TO TOP


“My grape’s leaves have weird spots, crinkly, upraised blisters on the top, and white and upraised on the bottom of the leaf. What’s up?” July 6, 2009

curlGrapes are hosts for several forms of mite, and this is caused by one. The damage is more reminiscent of  fungal damage, but it is not. This particular pest goes by several names; rust mite, erineum mite, and eriophyid mite. Each of the spots, or blisters, is a colony of these very small, worm-like mites. They generally do not cause a great loss of fruit, and is not an alarming problem in agriculture. This can be treated with dormant oils, and some publications list wettable sulfur as an in-season control.
curl
Front and back of grape leaf with erineum mite colonies.

BACK TO TOP


“My plum seems to be diseased; it has curly, blighted-looking new leaves. What is going on?” May 25, 2009

Plum leaf curlPlum trees, both fruiting and flowering types, are sometimes susceptible to several leaf-affecting diseases, including the disease known as plum pockets (Taphrina communis), which is similar in appearance to peach-leaf curl (Taphrina deformans). It causes distorted new growth (which is quite unsightly) and ugly, bloated fruit, and drains the energy of the plant. In agriculture, this is usually not a serious issue, but as an ornamental your plum can suffer greatly. Once the symptoms show, control is difficult, even with fungicides. Dormant spraying during the fall and winter (before any spring growth) with copper-based fungicides can improve the plant for the following growing season. Also, clean up under the plant in the fall and winter, and avoid excessive wetting of leaves or too much shade.

BACK TO TOP


“What perennials will bloom most of the summer?”July 13 , 2009

There are several options for sunny spots. Coneflowers (Echinacea), hardy Geraniums, Pincushion flower (Scabiosa), Yarrow (Achillea), and many forms of Salvia top my list. For shadier spots the hardy Fuchsias are your best option, though there are new forms of Bleeding Heart (Dicentra ‘Burning Hearts’ or D. ‘Ivory Hearts’) that bloom a long time, and Spiderwort (Tradescantia) has a fairly long season, if not really all summer long. I have also long been a fan of tucking just a few annuals into perennial beds to ensure a dash of color at all times.

BACK TO TOP


“Can you recommend any indoor plants good for lower lighting?” July 13 , 2009


This might be the most frequently asked question for indoor gardening. Amongst what we sell, Sanseveria, Philodendrons and Pothos (Scindapsus), and Cast Iron Plant (Aspidistra elatior) probably top the list of most reliable options. The rubber tree (Ficus elastica), Chinese evergreens, (Aglaonema) and peace lilies (Spathyphyllum) are also sometimes recommended, though I feel these are better in at least medium light. Remember that plants grown in dimmer spots often need less frequent watering than those in brighter conditions, so don’t overwater.

BACK TO TOP


“It’s mid-summer, and my lawn is getting patchy. Is this a good time to seed?” July 13 , 2009

The easy answer is no, it is not a good time. That said, many people chose to do so because they find their lawn unsatisfactory, and want to try even if success is not assured. Fortunately, grass seed is not too expensive.

If you should choose to overseed (adding new seed to an established lawn) in summer, there are a few things to remember. Before laying seed, it is good to weed, rake out excess debris, and if necessary dethatch. Once the new seed has been spread, put a very thin layer of fine mulch (1/8th of an inch or so) down with it.

At this point the watering becomes the tricky part. Your established lawn does not need very frequent water, but the new seedlings, once sprouted, have very little real roots. They should be watered frequently enough so that the soil surface stays moderately moist, perhaps as often as daily.

This tactic may help the lawn to be somewhat fuller, but if you are doing a major renovation of your lawn, it may be best to simply wait until temperatures cool in early autumn. That is one of the best times to start lawn.

BACK TO TOP


“I have earwigs in my garden! Yuck! What do you recommend for killing them?” July 27 , 2009

Earwigs are a plant pest, in the sense that they do sometimes chew small holes in leaves and flowers, and sometimes in ripening fruit. That said, the majority of their food is decaying plant matter and smaller insects.

They do serve a relevant place in the food chain, and in minor cases I generally don’t recommend treatment. Sometimes they decide they really like a particular plant, though, and they seem to be swarming it. I have witnessed this with dahlias and roses, and they have other preferred plants as well.

If you decide that your population merits chemical control, then an insecticide containing pyrethrins, a pyrethroid (B-cyfluthrin, for example), or Carbaryl (known in the trade as Sevin) can reduce or eliminate the population. Please note cautionary statements on the labeling or these inseceticides, especially if used around edibles.

BACK TO TOP


“My beets and chard have weird patterns in the leaves, what’s up?” July 27 , 2009

mites If the problem looks anything like this picture, it is leaf miners. They are the larval stage of several different insects, including some beetles, flies, and moths.

The more common types for chard and beets is the spinach leaf miner (yes, it also infests spinach), or Pegomya hyoscyami. The larvae chew the leaf between the upper and lower leaf surfaces, leaving a trail of sunken tissue that is sometimes dessicated.

The adults also cause some piercing damage to the leaves. In the case of beets where only the root is intended to be eaten, this is not serious, as long as the plant has sufficient green tissues for energy processing. Where you intend to eat the leaves, this can be unappetizing, especially when you find out that there are larvae in there.

Spraying the plant once the trails are noticeable doesn’t help very much, as the insect larvae are protected between plant tissues. Malathion and Spinosad are somewhat effective as sprays if they contact the insect, and can help to some degree with the adults.

Physically crushing the larvae inside the leaves is effective, but tedious. Thorough clean up of plant debris after harvest is a good management technique, and using row covers (thin, white gauzy blankets; we sell them) in spring and early summer can deter the larvae setting in.

BACK TO TOP


“My dogwood tree is wilting, but I am watering it regularly. What’s up?” July 27 , 2009

Sometimes dogwoods wilt simply from heat stress, even when the roots are kept moist. This is more apparent in areas with nearby concrete or other particularly hot sites. There is little to be done about it.

Often seeing a wilting plant makes a person want to instantly water a plant, but this is not necessary if the soil is moist. Excessive watering can lead to overwatering, and can lead to leaf drop, root rot, and sometimes death. It is of course true that plants need more water when it is hot, but the decision to water should be based on current soil moisture, not simply wilting of leaves in this case.

BACK TO TOP


“Is it safe to plant in this heat?” Aug. 3rd, 2009

In August, everyone is talking constantly about the heat; especially this past week. If you asked around, you would hear different things from different nursery people about the subject. They are probably all partially correct in some way or another (including me, and as I write this I can imagine people’s differing opinions as they read it).

You might hear that there is no difference to the plant whether it is in a pot or good soil in the ground, as long as there is attention to the plant’s needs, especially water. This seems somewhat true on the surface, but the problem is that to plant most plants correctly, you should somewhat disturb to root ball to prevent the roots from continuing to grow in a circle, and this disturbance (as well as any root breakage you might cause in the process) can be the difference between a hydrated plant or not. Add to this the human instinct that plants in the ground don’t need water as often; but your brand new planting can’t access ground water in general. If you choose to plant, be gentle to the roots and water the new plant (even if not the whole area) often.

On the other end of the spectrum, some nursery people say that one simply should not plant new hardy plants (perennials, trees, shrubs) during the summer at all. There is nothing wrong with taking a plant home and leaving it in a pot until the autumn “planting season”, as long as the gardener will attend to the plant’s fairly high maintenance needs, especially for water. I personally have planted in the summer before, often but not always with success.

What a gardener cannot do is plant in the summer, and then expect to be able to go on vacation shortly after, leaving the plant with no care. I cannot recommend disturbing a plant during periods of very high heat, but do not feel that summer planting is out of the question either. Note that transplanting or dividing plant in the ground, where severing the roots is necessary, is definitely not recommended during summer.

BACK TO TOP


“Can I still plant more lettuce?”  Aug 3rd, 2009

Lettuce can, in theory, be started almost any time of year. The extremes of summer heat and winter weather can make it a daunting process, but even then it can be done. If you reference our vegetable gardening calendar, you will see lettuce appears in the column for almost every month.

Some salad-loving gardeners start a new batch of lettuce from seed every week, and if some of the crops get damaged or ruined by extremes of weather they simply shrug and start more.

One of the problems that can arise in summer heat is early bolting. Bolting is the process of such plants trying to bloom, and they send up a spike-style blossom in the middle of the plant. Once they do this, the flavor of the leaves can be ruined. That is why some gardeners and professional growers harvest whole heads of lettuce at a time, instead of just picking a few leaves off here and there. In summer it is sometimes beneficial to harvest lettuce fully, and sometimes a little earlier than you might otherwise. The plus side of bolting is that if you leave it for a while, you can get more seed from them and do not have to buy more seed.

BACK TO TOP


“My tomatoes are ripening, and the ends are brown and kind of mushy. What have I done wrong?”  Aug 3rd, 2009

This is a fair description of Blossom End Rot, a disorder that affects tomatoes, cucurbits (squash, etc), and peppers. It is caused by a number of problematic conditions, and you can only affect some of these. First are the weather considerations, which you cannot change. Rapid fluctuations in temperature can cause this, and this can sometimes be problematic on the first batch of tomatoes that have been forming during chaotic weather in late spring/early summer.

Other considerations are the watering and the consistency of soil moisture. Of course, heavy rains that come late can do this, water-logging the soil, but it is usually caused by inconsistent watering techniques. If the soil stays quite wet or quite dry for significant periods of time than this can occur on ripening fruits. Moderation in soil moisture is the key.
Finally, we need to consider the presence of available calcium in the plant or soil. If the plant is calcium deficient, blossom end rot often occurs.

This can be prevented by adding lime when planting (even better, amend the soil you will have tomatoes in well before planting), or by using calcium sprays that you spray directly on flowers when they are open. The addition of calcium is a preventative measure, and cannot help tomatoes that are currently ripening. Fruit already affected cannot be fully saved, but the unaffected portion of the fruit is still edible.

BACK TO TOP


“This volunteer plant (weed?) has sprouted, and is now blooming and growing fast. Should I get rid of it?” Aug. 10, 2009

These pictures are of the plant commonly called Pokeweed (Phytolacca sp). PokeweedIt does grow around Portland as a self-spreading weed. Though it is quite pretty, especially when the berries form, but it is also quite poisonous. Both the berries and the roots have a dangerous concentration of poison, and some reports show the reddened stems as poisonous too.

PokeweedBecause these berries might be attractive to kids, we recommend removing this plant.

BACK TO TOP


“My pumpkins are shriveling up and falling off the vine just as they start to grow. Why?”   Aug 10, 2009

It’s not just pumpkins, but this happens to squash and cucumbers, and most of the vining, fruit-bearing vegetables. In some cases the fruit is instead small, tough, or malformed. The problem lies in the flowers not getting pollinated. The male and female flowers are separate from each other, even though they can form on one vine. Sometimes you will have only male flowers at a given time, making fruit production temporarily impossible. Sometimes the pollen doesn’t get from the male flowers to the female flowers. You can help with this part if the bees and such aren’t taking care of it, by spreading pollen with cotton swabs or some such tool.

BACK TO TOP


“Some of my tomatoes are growing very strange protrusions out the bottom of the fruit. What‘s up?” Aug. 17, 2009

tomato

This photo is from an actual tomato that was brought to our information desk at our Stark street location. We weren‘t sure exactly what to make of it at first, but some research yielded a pretty good idea. It is caused by a mutant recessive gene, generally called CLAUSA. To avoid too much technical jargon, it appears to be a mutation in the fruit that occurs when flower grows indeterminately instead of ending when the ovary is produced. In simple terms, the flower tissues continue to grow past when they are supposed to. It is a disorder but not a disease, and does not spread between plants. For more information about this, you might try an internet search with the keywords tomato, CLAUSA, and mutation, or some similar keywords.

“What do you have in way of tall, narrow evergreens, and can any of them tolerate a fair amount of shade?” Aug. 17, 2009

Sky PencilA few people have requested such plants recently, and here are some of the options we stock. Two forms of holly, the Ilex crenata ’Sky Pencil‘ (sometimes called ’Sky Sentry‘ - shown here ) and the Ilex vomitoria ’Will Fleming‘. Both get several feet tall, but rarely wider than a foot, possibly a foot and a half. Also, there is a boxwood - Buxus s. ’Green Tower‘ that behaves similarly.

Irish YewFor conifers, several forms of Yew and Cypress qualify, as well as the often used arborvitae - Thuja occ. ’Emerald Green‘. Probably our best yew is the narrow Irish Yew - Taxus bac. ’Fastigiata‘(shown at here), which slowly grows possibly to 20 to 30 feet tall and several feet wide, but is usually kept hedged to almost any height and width.

The yews have the additional bonus of tolerating shade quite well. The Italian cypress - Cupressus sempervirens rarely needs significant pruning, being a narrow column to about 25 feet tall and only 3-4 feet wide.

“What do you have in the way of onions?” Aug 17, 2009

We are selling six-packs of seed started onions at this point, and will have onion sets available in September, as well as garlic sets. As we get closer to autumn, most plantings of these items are for an overwintered crop, giving you an early harvest next growing season. This extends the season that you will have fresh onions next year.

BACK TO TOP


“My shrub wilted and lost most of its leaves. I’m keeping it really moist now; what else can I do?” Aug. 24, 2009

The first issue here is that the plant defoliated, presumably because it was not watered enough (note there could be other reasons). If a plant is very dry it drops leaves to protect itself from further drought stress, in effect lessening its need for water.

Many gardeners water a lot more at this point, and that is not necessarily good for your plant. Certainly the soil should be thoroughly moistened once after drying fully, but after that the plant’s need for water is lessened because it has less leaves.

Watering again before the soil surface has dried thoroughly is basically overwatering, and if this is done continually, you can cause far greater damage than the drying caused, possibly ending in root rot and the death of the plant. It is good for the gardener to try to remember that soil moisture is one of the keys to plant success, and that adding water when the soil is still moist can be damaging.

I should also address the second part of the question; what else the gardener can do. The answer is, well, not much. Fertilizer is usually not a good idea when the plant is stressed, and there are no sprays or what not for this sort of damage. Once the plant has stabilized and is starting to grow back, then fertilizer can be applied to encourage it to grow faster. Please note that fertilizer applied in autumn can sometimes lead to weak, excessive growth just before frost, and this can result in dieback.

BACK TO TOP


“There are notches bitten out of my rhododendron leaves. What is going on?” Aug. 24, 2009

Root Weevil damageRoot weevils are a common pest of rhododendrons and well as many other shrubs and some perennials. The adults cause damage as shown here, but this is the minor problem. The bigger problem is that the larvae eat the roots of your plants (thus their name) and can do such extensive damage that plants sometimes fail altogether. Most spray pesticides are not especially effective because they do not contact the weevil, and the adult beetle feeds at night.

One of the better defenses is beneficial nematodes (sold here and other garden centers in spring and autumn, autumn applications are most effective), which is a living parasite that can be applied to soil to kill the larvae. Please follow application instructions for nematodes and avoid exposing them to direct sunlight. Some spray pesticides can be useful for controlling adult population; please enquire of a nursery professional for a proper choice.

BACK TO TOP


“I’m interested in a Crape Myrtle tree. What do you carry and what should I know about them?” Aug. 31, 2009

Crape Myrtles (Lagerstroemia spp.) are a group of summer blooming shrubs and trees that are very showy this time of year. They are mostly upright and vase shaped, like many large multi-stemmed shrubs. Some can reach 15-25 feet tall, though shorter forms are becoming more common for gardens. Powdery mildew can be a problem for some, especially the naturally occurring species, but most modern garden hybrids have good resistance.

For taller growing types (15-20 feet tall) that we stock, look for ‘Centennial Spirit’, ‘Red Rocket’, ‘Muskogee’, or even the very large ‘Fantasy’ at 30-40 feet tall. For smaller types, usually less than 10 feet, look for ‘Watermelon Red’ or ‘Catawba’, and for true dwarves, usually no more than 5-6 feet tall, look for ‘Dwarf Purple’, ‘Petite Plum’, or ‘Acoma’.

See our shrub pick of the month feature on Crape Mrytle

BACK TO TOP


“I’ve seen what look like tropical Hibiscus flowers in people’s landscapes lately. Are they actually hardy?”
Aug. 31,2009

The best known tropical hibiscus is the Hibiscus rosa-sinensis, sometimes called Chinese Hibiscus or Hawaiian Hibiscus, and is not a hardy shrub. It should be grown as a container plant and protected from winter weather indoors (it makes a fine houseplant) or in a greenhouse.

There are some hardy forms of Hibiscus, however. Hibiscus moscheutosProbably what the question refers to is the Hibiscus moscheutos (shown in picture). It dies to the grown in winter, but returns in the spring (an herbaceous perennial) and blooms in late summer, with flowers up to 6-8” across. They come in white, various pink, and red blooming cultivars. The Hibiscus mutabilis and Hibiscus syriacus are also hardy shrubs in our region.

BACK TO TOP


“My cypresses are failing. They are browning from the inside out towards the tips, even with regular water, and only some of them are failing. What is going on?” Aug. 31,2009

This information, along with some question and answer about the spot the plants are in and other useful data shows something that we hear with some regularity, especially with conifers. Even with regular water and reasonable care, they seem to fail. It is also somewhat common (and frustrating) with arborvitae hedges.

Usually what causes this is overwatering, poor draining soil, or planting the shrub or tree too low. All of these can cause root or stem rot and lead to the systemic failure of the plant. It looks like the plant is dry because the unhealthy roots or stem cannot transport water efficiently, and as far as the leaves or needles are concerned, they are too dry.

Poor draining soil can be somewhat corrected by adding both organic matter and drainage materials (pumice, gravel, etc.). As for low planting, never bury the stem of a tree any more than it already is, and never pile water-holding mulches up around the trunk. If you are ever purchasing a bare-root tree, ask a nursery professional to show you how far it should be buried.

BACK TO TOP


“There is a very pretty and fragrant tree blooming around the neighbor. What is it?”   Sep 7, 2009

ClerodendrumThis time of year, that question usually refers to the Glorybower Tree, or Clerodendrum trichotomum. This small tree is fast growing, hardy, fragrant (sometimes it smells like peanut butter!), and generally a crowd pleaser. The fruits will soon replace the flowers, and they are the best part. We do carry them and have some nice ones for sale now, but quantities are limited.

Clerodendrum trichotomum in fruit

BACK TO TOP


“When will the fall flower bulbs be here?”   Sept. 7, 2009

We have been hearing this for the last while, and now I can say that they are arriving. Much of our stock for the season is here and ready for sale, with more coming in the next two weeks. Now you can get those tulips, daffodils, and others that you have been waiting for.

The vegetable “bulbs” such as onions, garlic, and potatoes will be here soon, approximately the middle to second half of September.

BACK TO TOP


“I am harvesting my summer vegetables now. What can I do with the space?”   Sept. 7, 2009

There is still time to plant certain fall and winter vegetables including lettuce and other greens, radishes, onions and garlic for overwintering, and others. Please reference our vegetable planting calendar for other ideas. Alternatively, now is a good time to think about getting started with an overwintering cover crop, such as white or crimson clover, fava beans, and buckwheat.

We sell these and several others this time of year. Also, it might be a good time of year to think about and hardscaping changes you might want to do in your yard. Are you happy with the vegetable beds? Want to build raised beds? Now is a good time for such projects, and for amending soil with fresh compost or mulch.

BACK TO TOP


What poisonous berries are in our area? Sept. 14, 2009

photoPokeweed-This weed spreads by seed and comes up seemingly at random in different places year to year. Many parts of the plant are highly toxic, especially the berries and roots. When this is found on your property, we recommend removal, using full body clothing and gloves as a precaution. Sometimes children are attracted by the bright color of the berries.

photoEnglish Laurel-These common screening shrubs have an almost black berry this time of the year that contains significant toxins. Though they are often too high up to be a threat to children, plants on your property could be searched for any low-lying berries that children might be attracted to. Toxic English laurel berries ripen to black

photoEnglish Holly- Despite their use as holiday decorations, these berries are toxic.

photoYew berries- The pits of yew berries are very toxic. The bitter taste can turn off most ingestions, but it still one to teach your children to avoid.

photoNightshade- This pretty vining weed has quite pretty flowers followed by red to purple red fruits. Unfortunately, the fruits are quite poisonous. We recommend removing this plant from your property, making sure the seeds do not fall and sprout.

BACK TO TOP


“What vegetables can I still start for my fall and winter garden?”   Sept. 28, 2009

It is too late to start most vegetables from seed at this point. As for started plants, most greens can still be planted, such as lettuce, cabbage, kale, arugula, and the like. This is an ideal time to put in garlic and onions for an early harvest next year, and we have a great selection. There might still be time to grow short season radishes, but that will depend on the temperatures in the next few weeks. Also, this is a great time to put in a cover crop to prevent excess winter weeds and, in some cases, fix nitrogen into the soil for next year’s crop.

BACK TO TOP


“My rhododendrons and some of my vegetables have notching cuts out of the sides of the leaves. What is causing this, and how should I treat for it?” Sept. 28, 2009

Though we covered this early in the growing season, we are still seeing a lot of samples of this sort of damage. This is caused by the feeding of adult root weevils, actually a beetle.

WeevilsThe shown damage is essentially superficial, but the real problem lies with the weevil, which eat the roots right off the plant. In extreme cases this can kill plants, even established shrubs. Small vegetable plants can succumb quite easily. It can be treated with beneficial nematodes, a microscopic parasite that eats the weevils. This treatment is most effective in spring or early summer, but is often used in autumn as well. Insecticidal drench containing the systemic insecticide imidicloprid can be effective for ornamentals such as rhododendrons, but is not recommended for edible plants.

BACK TO TOP


“My apple tree is almost ripe and ready to pick. Should I prune it right afterward?”   Sept. 28, 2009

Apples should generally be pruned in the winter, not early autumn. It is recommended that you wait until the plant is fully dormant. Most apples fruit on spurs, the small knobby branch-like structures that grow just off moderate sized branches. When the spurs become overcrowded, thinning can create better fruit development the following year.

Any branches that are growing too tall or long for the desired size and shape of tree can be shortened in the winter as well. Apples should also be summer pruned, removing much of the new green growth that grows up above the fruiting spurs, unless you want a new branch to develop there.

Be aware that this summer pruning is of sort, supple new shoots; no major branches should be removed in the summer.

BACK TO TOP


“The primary questions that people are asking right now have to do with apple tasting, which is right around the corner. I invite our readers to preview our apple info page for information regarding that.”   Oct. 5 , 2009


Apple Tasting webpage:

http://www.portlandnursery.com/events/appletasting.shtml

BACK TO TOP


“I want to move my established rose shrub to a new place in the yard. When should I do this and what should I know about it?”   Oct. 5, 2009

Roses can be moved in autumn without too much trouble. They should be moved later in autumn, the middle to late part of October or the first part of November. More precisely, it is best done once the season has definitely cooled off but before it has rained so much that the soil will be saturated. Before digging up the rose, have the new site prepared. This means get the soil loosened and mixed with compost.

It would not hurt to add a bit of bone meal or organic granular transplanting fertilizer, but quick acting fertilizers are not recommended for this. Cut the rose bush back to about 18 inches tall, pruning as you otherwise would in February. Then dig up the plant, keeping as much of an intact root ball as you can manage. Move the plant promptly to the new spot, making sure the soil level as it relates to the bush stays the same; don’t bury the stem.

Water it in afterwards to settle the soil, and apply a thin layer of mulch; again, don’t bury the stem. The plant shouldn’t need further care until spring growth starts.

Some shrubs handle this sort of treatment better than others. Roses, butterfly bushes, Hydrangeas, and willows survive transplant fairly easily. Established large shrubs such as Viburnum or Hibiscus syriacus have a harder time. Established conifers often transplant poorly and don’t have a particularly high survival rating. Part of the trick is to get an intact root ball of sufficient size for the shrub. Dwarf plants often move easier than their larger counterparts.

BACK TO TOP


“What grasses can I grow that are evergreen?"    Oct. 5, 2009

For a larger growing grass, Pampas grass (Cortaderia sellowiana) is the lord of the grasses. They grow up to 15 feet tall and bloom with spectacular white plumes, each as big as your arm. They thrive in full sun and are drought tolerant. Note that the common name comes from the Pampas plains in South America, and the plant is not ‘Pompous grass’.

For a more modest sized plant, probably the most reliably evergreens are some of the sedges (Carex). I particularly note Carex morrowii and Carex buchananii, the former with a thick leaf, the latter with almost hair-like growth.

Note that some of the deciduous grasses look great even after they turn brown. Of particular note are the maiden grasses (Miscanthis sinensis) and the fountain grass (Pennisetum species). Remember that the Purple fountain grass is not hardy, but the green ones are.

See our features on Carex and Pennisetum.

BACK TO TOP


“I’m planting some tulips this fall, same as I almost always do. Some of them don’t seem to come back over multiple years. Are some better than others?”    Oct. 5, 2009

Sometimes tulips do have trouble in our soils over the long term. They have been extensively hybridized, just like roses, and some of them have lost hardiness features. To ensure a better survival rate, look for either Darwin Hybrid tulips or species tulips (those types which occur in nature, not products of our hybridization).

BACK TO TOP


“I have a lot of bugs suddenly invading my home, both inside and on the siding outside. What is it, and what should I know about these?” Oct. 26, 2009

Brown stink bug
Brown Stink BugSeveral of our customers have complained of these invaders recently. This is an actual bug (an insect in the order Hemiptera ), it is not just called that because it is an insect. It is normal for them to seek warmer or protected areas with winter approaching.

Though many species eat plants, they are not a major plant pest in the home garden. They are not dangerously harmful to humans but can release a foul smell when disturbed and some reportedly do bite if handled. Most people do not like them in their home, of course. If you choose to trap and release, use caution to avoid the smell being released.

Pyrethroid sprays can often kill them and some are labeled for household use, though I don’t recommend overuse indoors. Caution; these sprays often stink.  The one we carry that is labeled for this pest contains the chemical pyrethrin.

BACK TO TOP


“What is that brilliant red, almost pink, shrub I am seeing around town?”    Oct. 26, 2009

Burning bush showing its fall color

EuonymousThis refers to that king (or queen) of fall color, the burning bush (Euonymous alata ‘Compacta’). It has some the most impressive color around this time of year. It is considered fairly unremarkable the rest of the year, having no impressive bloom or fragrance, but everyone suddenly wants one in autumn.

They grow to a moderately large shrub about 5 feet tall and wide. There is also a larger version that is less popular in urban gardens. It is a very easy to grow shrub that takes no unusual care.

Other shrubs and trees with noteworthy fall color include Maples, Dogwoods, Stewartia, Viburnum, Ginkgo, Oak Leafed Hydrangeas, and Crape Myrtles.

BACK TO TOP


“Can I move a large, established shrub at this time? I was told it was bad during hot weather, but is now a good time?”Nov 9, 2009

If you decide that you want to move an established shrub, this is one of the best times to do so. The soil and air have cooled, but the rains are not so very abundant that the soil is saturated. At this point, the sooner the better; it is not to advantage to wait until midwinter. That being said, it is not horticulturally a good idea to move a large, established shrub, ever. There is always a risk that you will simply kill it because you will be severing a significant amount of the root ball. It is easier with smaller shrubs, or with shrubs that grow from suckers such as hydrangeas. If it is move it or kill it, then so be it. If you can live with the shrub where it is, that is my true recommendation.

BACK TO TOP


“My ornamental grass has turned yellow and brown. Do I need to cut it back now?”   Nov 9,2009

A lot of people like the way the grasses look after they change, so it is fine if you want to leave the grass for a little while. The grass can be cut now if you don’t like the look. Always leave a tuft of about 10-20% of the total height of the grass. Do not shave it to the soil line. If you choose to leave the grass, it will need to be cut by February so the new spring growth can come up without competing with its own dead tissues for sunlight.

BACK TO TOP


“Should I be laying down mulch now, or am I late?”Nov 9, 2009

November is a good month to lay down your winter mulch. Doing it sooner can keep the ground warm longer than it should, and doing it too late may mean that the plants will experience their first cold snap without the benefit of a mulch blanket. Remember that compost or composted organic matter is usually best for soil quality, while bark products help with weed prevention. Do not pile mulch around the trunks or trees or shrubs, but this is a good idea for herbaceous perennials (those that go away completely for the winter).

BACK TO TOP


“What should I be doing to prepare my garden plants for winter and cold weather?” Dec 7, 2009

This question, put to us in many forms, has been the dominant thing we have been hearing from our gardening customers. Some have asked about hardy bananas, some about pruning trees or roses, and others just aren’t sure what they should be doing. I will try to cover some of the basics that gardeners should know right now.

Firstly, this is a great time to lay mulch in the garden, if you haven’t already. A layer of composted garden mulch or bark helps to protect the shallow roots in soil from being damaged by freezing air temperatures. It acts something like a blanket to trap some of the heat in the soil, keeping the soil temperature above freezing even when the air temperatures are temporarily below it.

Please note that neither soil nor plants actually make body heat as we do, so the blanket effect is only to trap existing heat, not continue to make and hold heat the way we do in our beds. It is alright for the mulch to partially cover most perennials but it should not bury the wooden stems of trees or shrubs. During extended cold snaps the soil can still freeze, but there is little you can do about this or the possible damage that can happen to plants. Keep in mind that deeply rooted plants such as established trees and shrubs should have no problems with this; it is never cold enough for long enough here to truly freeze the earth like in the tundra.

Often our coldest weather around here comes with dry air and clear skies, sometimes with high winds. Make sure the soil around your plants is moist during these times. Moist soil is a better insulator than dry soil. Even if the water in the soil freezes, it is still better off moist. Plants that are in portable containers can and should be protected during hard freezes. This might mean moving temporarily to garages, sheds, or up against the house. This should not mean in the house in warm air; that would be very shocking to the plants.

Some people like to cover or wrap their plants during cold snaps. This is fine and can temporarily trap a little bit of heat, but the key word is temporarily. Again, the plant is not making body heat to replace any lost heat. It does have the advantage of keeping some of the wind off of the plant, reducing damage from wind chill. Covers and wraps should be temporary and should not be used during our ordinary chilly, drizzly winter weather. They can trap moisture on the plant and can encourage rot.

Roses and other plants that may be overgrown can be partially cut back now. This is primarily to keep the plants from whipping around in the winter wind. In the case of roses, the actual pruning should be done in February before new growth starts. Some trees and shrubs like to be cut back now, and some prefer late winter (and for some, either is fine). If you have particular questions about your plant type feel free to contact us.

Hardy bananas are one that people are often not sure what to do with. The leaves will turn to mush at the first hard frost; there isn’t really any getting around this. You should mulch around the plant to protect the roots, but they should survive without too much trouble or work. The tricky part is getting the stalks to live through the winter and grow to their full potential, which can take 2-3 years. Some people wrap the stalk with burlap. I believe that this only helps with the wind chill and should only be done during especially cold weather. In moderate weather it can trap moisture and encourage rot.

One thing that some people do is to put a black plastic bag over the tip of the stalk and cinch it onto the stalk. The purpose here is to keep excess rainfall out of the growing point. It should be done when the growing tip is dry. Understand that the growing tip of a banana plant acts like a small cup and can hold moisture. Constant moisture there with moderate temperatures can mean a rotten tip and therefore a ruined stalk. Keeping the tip dry for the coldest, rainiest part of winter might help prevent rot. Note that the wrap should only be on for a couple of months when it is coldest, say in December and January. It should not be there in late winter when the plant might try to start growing. Also, do not use clear or white plastic, or anything see-through. This can cause the greenhouse effect and make the growing tip very warm.

BACK TO TOP


“What houseplants do you have that are quite easy to keep alive?” Jan 4, 2010

There are a number of options to fit this bill. Sanseveria (Snake Plant) is possibly the easiest to grow houseplant there is. Just don’t keep them wet or cold, and they will be fine in almost any situation. Philodendrons and Monsteras are quite easy, and their cousin Scindapsus (Common Pothos Vine). We recently received a shipment of plants with some very interesting forms of Philodendron, and we would love to share them with you. Aglaonema (Chinese Evergreen) is a very reliable low, full bush. For taller growing options, look to Dracaena marginata (Dragon Tree) or Ficus elastica (Rubber Tree).

Don't miss our Houseplant Sale Jan. 22-24, 2010

BACK TO TOP


“What outdoor plants look especially good this time of year?” Jan 4, 2010

There are a surprising number of plants that look really good in the wintertime. The better known choices include pansies, hellebores, and camellias, and they are all great. There is much more however. Lonicera fragantissima, the most fragrant of the honeysuckles, blooms in mid winter and is exquisite. hamamelisWitchhazels (Hamamelis) have some of the most impressive winter flowers on a large shrub or tree. There are also many shrubs with great winter berries. Look for Coral berry or Snow berry (Symphoricarpos spp.), Beautyberry (Callicarpa b. ‘Profusion), and Winter berry hollies (Ilex verticillata and other Ilex spp.).

See our plant features for winter interest:

Beauty Berry

BACK TO TOP


“The weather has been so perfect. Can I plant my summer vegetables early?” Feb 29, 2010

No. No, no, no. The afternoons lately have had fantastic weather, and it has been a blessing for us. Some of the hardy plants have broken dormancy early, and it is really looking like spring out there. That is all well, but it is still getting really cold at night, in some cases freezing. While you can purchase tomato and other seeds now, we do not have started plants. So: no tomatoes, basil, peppers, squashes… no, no,no.
It is an appropriate time to start many root crops, such as potatoes and onions, as well as peas.

As we get into March it becomes a good time for cool season green vegetables, such as lettuce and other greens, and brassicas (cauliflower, broccoli, etc.). See our vegetable calendar for more data about this.

BACK TO TOP


“Some bugs are eating the new growth of my plants already. Aren’t they all asleep in the winter?” Feb 29, 2010

Most of them are dormant, but we are seeing a fair amount of slug activity, and a lot of cutworms. Both of these pests can do considerable damage to new growth on perennials and other plants. Some species of cutworms climb in taller plants, and do damage surprisingly high off the ground.

Both of these pests are active at night, so can be hard to readily identify. Flashlight hunting can be helpful to figure out which problem you might have. Also, cutworms hide during the day just under the surface of the soil, often near their dinner. Slugs sometimes leave tell-tale slime trails. Either way, we have pesticides and other options for minimizing the damage to your plants.

BACK TO TOP


“I am planting trees in my parking strip, and the city wants me to plant 2 inch trees. What does that mean?” Feb 29, 2010

There are regulations made for parking strip trees, and it is best to communicate with Portland Parks and Recreation before actually purchasing or planting a tree. There is a permitting process that you go through. A two inch caliper tree means that the diameter of the trunk of the plant is two inches, when measured about six inches above the ground, and measured above the graft (the knotty looking thing just above the soil on many trees). Most of the trees we sell are not two inch caliper, though we have some that do qualify. Please feel free to inquire with us as to availability.

BACK TO TOP


“I recently moved into a new house, and my neighbors aren’t exactly what I dreamed of…What do you have in the way of quite fast-growing shrubs for privacy?” March 29, 2010

This is a very frequent question we get year ‘round. Amongst the fastest (but largest, careful) options are the English Laurel (Prunus laurocerasus) and the Photinia fraserii. Note that while these will fill in quickly, they have their down sides.

The Laurel grows to about 25 feet tall and 10 feet wide, and is a fair amount of work to maintain at a smaller size. It is also on the city of Portland’s nuisance plants list, but do not confuse this with the noxious weed list.

Photinia grows to about 15 x 15 feet and has nice new growth in the spring, but sometimes suffers from leaf spotting diseases. Another option is the wax leaf Privet (Ligustrum texanum), which is quite easy to grow and grows to about 12 feet tall if unclipped. For shadier spots, one might consider the Aucuba japonica, which grows to about 10 feet or so. There are of course a number of other plants for creating privacy, but most of the others (Arborvitae, etc.) are not so fast growing and take quite some time to fill in.

BACK TO TOP


“What herbs can I plant right now?”March 29, 2010

Most perennial herbs can be planted outside from started plants at this time. That includes lavender, rosemary, sage, thyme, oregano, and some others. Seeding of these plants is acceptable, but might be best indoors until they have sprouted. Cilantro and parsley are probably fine outside now as well. The one that is still not feasible is basil. Basil is very cold sensitive, and in some years will not thrive outside until June.

BACK TO TOP


“I heard that I have to get two blueberry bushes to get fruit. Is that true?” March 22nd, 2010

This is mostly true. A lone blueberry can grow a little bit of fruit, but the yield and quality will be much better with a pollinator. Not only do you need to get at least two bushes, but they must be two different types of blueberries that bloom at approximately the same time. For example, two Bluecrop bushes will not pollinate each other, but a Bluecrop and a Blueray will. They are categorized into 3 different categories, early-, mid-, and late-blooming. Sometimes an early- and a mid- will work together, but an early- and a late- will not. Please see our blueberry care and bloom schedule for more information.

BACK TO TOP


“My dogwood true hasn’t leaved out yet, but all sorts of other trees have. Is it dead?” March 22nd, 2010

Probably not, or at least the fact that it hasn’t grown any leaves is not an indicator of anything. Some trees grow leaves before others. We see so many cherry and crabapple trees blooming now that we think the other flowering trees should be too, but dogwoods come along later. Birches, beeches, and stewartias are other examples of late breaking trees.

BACK TO TOP


“What herbicide can you recommend for my weeds right now?” March 22nd, 2010

A little known fact about herbicidal sprays is that most don’t work in cooler temperatures. While the weather has been nice, I cannot say with confidence that most herbicides will work well this time of year. Most such sprays need temperatures above 60-65 deg F to work well. So, a hoe or other weeding tool may be your best bet right now. We do have an herbicidal spray product called ‘Weed Free Zone’ which is labeled to work in colder temperatures and may be an acceptable solution. Please always read and follow labeled directions and use herbicides responsibly.

BACK TO TOP


“What houseplants do you know of that will continue to be flowering in my house?”” April 19, 2010

The truth is that most flowering indoors plants are what should be called “gift plants”, which means that they look great when you buy them, but are often out of bloom, or sporadically blooming, within a few weeks of taking them home. This includes the indoor azaleas, hydrangeas, cyclamen, begonias, and others. It is not that these plants die upon entry to your home, but they will not look the same as when you bought or received them.

A few indoor flowering plants that can re-flower reliably indoors (with bright indoor lighting) include the African violets, flamingo flower (Anthurium spp.), and peace lily (Spathiphyllum spp.). These three plant types can bloom often with good care and regular fertilizer.

BACK TO TOP


“What groundcovers can do well under big fir trees? I’ve had trouble with trying a lawn there.” April 19, 2010

This can be a difficult place to garden, and many plants have trouble in it. Aside from the shade that the tree casts, this can also be a very dry gardening spot because trees are greedy for water, especially in the summer. Our top choices for spreading groundcovers for such a spot are Vinca, Ajuga, and Pachysandra. These are all shade tolerant (or preferring) groundcovers that can handle temporary dryness. Note that some summer water will still probably be necessary. These are spreading groundcovers; vinca especially can spread somewhat aggressively, but as a lawn alternative these are good options. .

BACK TO TOP


“I’ve been hearing a lot about this new re-blooming lilac, do you have some?” April 12, 2010

Yes! There are two new types of lilacs that re-bloom in the summer and autumn, ‘Bloomerang’ and ‘Josee’. We have not been able to get the ‘Bloomerang’ yet, but we have recently received some ‘Josee’. These pink lilacs grow to only approximately 5 feet tall and wide, and if you remove the spent blossoms in late spring, they can re-bloom in summer. We have limited quantities and availability, so get them before they are gone!

BACK TO TOP


“I want to garden with native plants, but I also want impressive flowers in my garden. What are some of the better options to combine these two ideas?” April 12, 2010

There are some plants that fill this request, but the majority of native plants have a woodland look, and are not necessarily grown for spectacular flowers. Some plants that qualify include Rhododendron macrophyllum, Ceanothus thrysiflorus, Flowering Currant (Ribes sanguineum and Ribes aureum), Camas Lily (Camassia quamash), and many form of Lupine (Lupinus spp.).

The first three options are medium to large shrubs that have impressive flowers, the last two are perennials. All of these flower between mid-spring and early summer, and they are all quite easy to keep in our climate once established.

Camas Lily   Flowering Currant
Camassia   Flowering Currant

BACK TO TOP


“What plants can you recommend for a new rock garden in my yard?” April 12, 2010

SaxifragaThis is a great time of year to be looking for rock garden plants, as most perennials that are best in rock gardens are in bloom right now. These include candytuft (Iberis spp.), rock cress (Aubrieta or Arabis), and Saxifraga (shown here).

Additionally, sedums and other small succulents make great additions are are particularly low maintenance. As for shrubs, there are plenty of compact miniatures that make great backbone plants for the rock garden. These include several forms of Hinoki cypress (such as Dainty Doll and Leprechaun) and Lawson cypress (look for Elwood’s cypress or golden surpise), as well as some dwarf mugo pines. Also, some broad-leaved shrubs can fit in well, such as the smaller forms or Hebe and Rhododendron, especially Rhododendron impeditum.

Pinus mugo ‘Valley Cushion’

Mungo

 

BACK TO TOP


“Aphids” May 24, 2010

AphidWow, there are lots of them out there, and they like a lot of garden plants. We have recently seen examples on apples, maples, plums, roses, honeysuckle, lupines, and a whole bunch of different vegetables. The thing about aphids is that they breed rather quickly this time of year, so even a little problem can become an infestation rather fast. They are almost always found on the new growth and flowers of plants only; rarely do you see them on older leaves.

AphidHere a few tips and recommendations for effective control. Firstly, with many plants you can simply cut the new growth/flowers off; you will get rid of most of the population just like that. This should be reserved for those sorts of plants that will readily replace what you are cutting off; don’t do this with slow growers. Sometimes a jet of water from the hose can knock aphids off of a plant, scattering them but not usually killing them. (Note aphids come in many colors).

As for insecticidal sprays, usually an insecticidal soap or pyrethrins spray will kill them on contact, though neither of these sprays have significant residual (lasting) effect. Note that both of these sprays accepted in organic gardening practices. The difficulty here is that they can breed their population back rather quickly, making repeat spraying a necessity. Also, ladybugs ( or ladybeetles, ladybirds…) are natural predators of aphids, though you cannot combine using ladybugs with using insecticidal sprays.

BACK TO TOP


“Coryneum Blight” May 24, 2010

Coryneum BlightAlso called shot-hole fungus. This is a disease that commonly affects many members of the genus Prunus, including cherries, plums, peaches and laurels. We have seen a lot of cherries being affected at this time. It causes a small brownish necrotic spotting on the leaf, which continues as the spot falling out of the leaf, leaving a hole (thus the name shot-hole). It is a significant disease that can drain quite a bit of energy from the victim tree or shrub. It is worst in warm but wet weather; avoid wetting leaves when possible, and avoid significant shading on the plant. Immunox is a fungicide that can help to keep this problem in check during the growing season.

BACK TO TOP


“Cutworms” May 24, 2010

Cutworms are notorious garden pests in our area, possibly doing more damage to home gardens than any pest save slugs. They are basically the caterpillar form of several species of moth. The moths are nondescript, but the worm can do a lot of damage to vegetables and annuals. They are named because they sometimes cut a plant off at the soil line, leaving part of the plant lying on the ground to die. This is disheartening to an excited vegetable grower to say the least.

Cutworm pupThey can be controlled by physical removal of worms and pupa (the red guy shown at right) from plants and soil, and by a number of different insecticides, some of which are acceptable for organic gardening practices. Note that the pupa will generally be in soil, so sieving the soil before planting can be of great benefit in limiting their damage.

BACK TO TOP


“Leaf spotting and leaf damaging fungal disease” June 21, 2010

Most of the questions we have received recently have had to do with leaf-spotting or leaf damaging fungal diseases, and I will focus on a few of these for the time being. Plants in the genus Prunus have been heavily affected, including cherries, plums, peaches, and laurels. The problems have included a lot of shothole fungus, leaf spot, and peach leaf curl (some of these are all ready pictured in our FAQ archives).

While different diseases have different controls, what we need most is some drier weather. The moderate temperatures of May and June combined with high humidity and frequent rainfall has made ideal growing conditions for many fungi. While we can’t do anything about the weather, we can do certain things to help the trees along a little. In the case of most fungal diseases, removal of heavily affected tissues (bad leaves) from the tree and from under the tree can help a lot.

Do not intentionally moisten the foliage when irrigating. Provide as much direct sunlight as possible for trees. Fungicidal sprays can be useful too; note that we cannot recommend a product without a specific diagnosis.

Other plants that are having such problems include apples (powdery mildew), tomatoes (early blight), and roses (black spot, powdery mildew. The above recommendations still apply as generally good cultural ideas.

BACK TO TOP

“I have a lot of clover I want to get rid of. What can I do?” July 2010

To tackle that question, I need a little bit more information. Is the clover in a space by itself? Is it amongst the lawn? Amongst other plants, such as your perennial beds? Under shrubbery?
If the clover is mixed into your lawn there are products that can kill the clover without hurting the lawn. These are called selective herbicides.

If you use one, make sure to read and follow the directions; it is possible to hurt the lawn (or yourself, for that matter) if it is misused. Also, make sure the lawn itself is hydrated and not severely stressed. These products should only be applied in dry weather during moderate temperatures (above 60 deg F, below 85 deg F). Also, I cannot recommend the use of herbicides near waterways.

Note that mowing higher can help the grass to compete with the clover. Also, be aware that the presence of some clover actually helps the grass to grow better by fixing nitrogen from the air, improving the grass’ ability to keep growing.

If the clover is alone, smothering it, taking the top layer of soil off and replacing it, or using a spray such as round-up can get rid of it. Also, weed block fabrics can be laid down in a non-garden area to keep it weed free. This can also work around established trees and shrubs, though it is not so great in perennial/annual beds.

If it is amongst desirable flowers, there is not much you can do except keep weeding. Try to get the clover roots up where possible. Also, keep in mind that any perennials that grow significantly taller than clover will not really suffer from its presence, although tolerating such clover can be inviting it to spread of course.

BACK TO TOP


“My hydrangea is not blooming this summer, but seems otherwise healthy? Why?” July 2010

The main issue here is pruning. When most hydrangeas are cut back in the dormant season, or even late in the past growing season, they are not likely to flower on the cut stems the following summer. Hydrangeas generally should not be pruned like a hedge or many other summer flowering shrubs.

For this reason, some people recommend a three year pruning cycle, where any healthy stem less than three years old is not pruned at all, and any that are three years old or older are removed entirely during the winter. The un-pruned shoots will flower the following summer, and the removed stems will be replaced by new fresh shoots near the base of the plant, which will flower once they have matured for a year. Good culture and an all-purpose fertilizer during the growing season will stimulate the growth of these new canes.

See our feature on Hydrangeas

BACK TO TOP


“There are a whole lot of these bugs all over my trees and/or siding of the house. They don't seem to be killing the tree, but… what should I do?” October 2010

During the autumn, particularly in late September and throughout October as the nights get colder, a certain class of insects tend to swarm. These are the typical bugs, or members of the suborder Heteroptera, and more specifically the shield and stink bugs, or families Pentatomidae and Scutelleridae(and related families).

Ok, the Latin aside, I'm talking about a group of bugs that usually have a back in the shape of a shield, with the young having a similar but smaller form to the adults. Some of these bugs are plant eaters, and in some cases can be agricultural pests, but they do not frequently do much damage in the home garden. When you see them swarming in the autumn it is usually because they are looking for a place to overwinter, often in cracks or under tree bark, or under siding (which they presumably mistake for trees). They may do some damage to leaves at this point, but remember that most leaves are falling of your deciduous plants soon anyway. Usually spraying insecticides is not needed or recommended.

If you are finding significant numbers of them inside your house, I can understand why you would want to control/remove them. Note that many of these bugs are called stink bugs, because they can emit a foul odor when disturbed. Also, it is often not advisable to use insecticides inside your home. Some people have had success controlling them by vacuuming them up with a hand attachment. You might consider being thorough about getting as many as you can at once, and then changing the bag shortly thereafter. Do this outside, in case they have 'stunk up' the vacuum bag. In the long run, they can be discouraged from entering the house by having siding/walls/windows that are fully sealed.

Some species of bug are invasive agricultural pests that should be reported to the Oregon Department of Agriculture, including the one shown below. If you wish to familiarize yourself with these, see the ODA website.

A brown marmorated sting bug, an invasive species that should be reported.

BACK TO TOP


“What can I do about my patchy lawn and what should I be doing with my perennials this time of year?” October 2010

Shield BugOctober is usually a fine time of year for adding seed to an existing lawn, or for starting a new lawn. If we get semi-warm to warm days, cool nights, and moderate rainfall, then conditions are perfect. Note that once the days are rather chilly or there is heavy rain, it may be getting too late. If you need a guide to starting a new lawn, download our brochure Installing a Seed Lawn.

As for perennial beds, it is mostly time to go to sleep for the year. Remove any brown, yellow, or diseased foliage. Diseased foliage should not be allowed to rot near the host plant, but clean leaves can. Do not remove green leaves, especially from evergreen perennials. Add mulch (compost for soil improvement, or bark for weed control) to the area once the soil temperatures are down, usually sometime in early to mid- November. Do not pile mulch next to the trunks or shoots of woody plants, as it can rot the bark of the tree or shrub.

BACK TO TOP


“There is a lot of powdery mildew on my…, what should I do?” October 2010

Powdery mildew affects many plant types, and that is why I left the name blank in the question. Regardless, the majority of the plants it affects outdoors are either annuals or deciduous, and I cannot recommend spraying such plants this late in the year.

Examples include squashes, which you are probably already harvesting, and bee balm, which will soon go dormant anyway. Note that removing infected leaves and getting them out of the area can cut down on the problem that reemerges next year. For roses, cut out and get rid of infected tissue, and consider spraying in spring and summer if the problem persists next year.

On those occasions where an evergreen is affected, such as Euonymus, the problem can be significant and ongoing. I can tentatively recommend spraying, but more sun and better air circulation are even better than fungicides. For this reason, some Euonymus make poor hedges but good accents or specimen evergreens. Note that rosemary usually does not get powdery mildew unless it is in heavy shade or indoors (it is not really a houseplant, by the way…).

BACK TO TOP


“What are these ugly moss-like things growing in my yard, and how can I get rid of them?” October 2010

LiverwortThe plants being referred to are actually a group of spore-producing (versus flowering) plants called liverworts (shown here). They are similar to mosses in habit, though they usually grow only on wet soil, not in trees or on rocks like some mosses can. Liverworts can grow to be a groundcover in shady, moist areas, and can choke out lawn under these conditions.

They behave similar to ground-growing mosses, but can grow thicker in some cases. The interesting palm-like structures are part of their reproductive system. We have seen a lot of this during the growing season, possibly because it stayed rainy all the way until July this year.

The best ways to control liverworts are similar to those for controlling moss. Allow more sun to the area, and do not irrigate unless necessary. Allow better air circulation if possible. It can be scraped off the top of the soil, taking about half of an inch of soil with it, which can be replaced with fresh soil or compost. Some moss or weed killing sprays may be effective at killing it, making it easier to scrape off. The product that we carry that lists it on the label is called Moss-Max. Please note that it will simply grow back if the conditions are not changed, and the area remains wet and shady.

BACK TO TOP


"There are a lot of mushrooms growing up in my yard. What are they and what should I do about them?" November 2010

There are many, many species of fungus and I cannot state any absolutes about such a broad category, but here are a few good guidelines. Most mushrooms that grow out of the ground in your lawn or garden are the fruiting, or spore-bearing bodies of soil-borne fungus. The fungus is often a network of fungal strands throughout the garden soil.

There are many species of fungus that grow this way, and many of them are beneficial to your garden plants, such as the various species of mycorrhiza fungus. In short, there is no reason to believe that mushrooms are automatically a bad thing, or pest in the garden. They are often a sign of soils that have ample organic matter and that have not recently been disturbed, aka good garden soil.

Some types of mushrooms are poisonous, so it may be best to mow them or knock them down if there is risk of children eating them, or if they are just plain undesirable to look at. They will not continue to grow once the cold of winter has set in. There are not any pesticides available to the public that will prevent mushrooms from coming back, so physical removal is the only thing that is generally recommended.

BACK TO TOP


"What can I do to help winterize my plants?" November 2010

There is only so much one can do for plants that are in the ground. Mulching with compost or bark in November can put a layer of protection between freezing air and the roots and crown of plants. This is especially good for perennials, but don't pile mulch directly against wooden trunks of trees and shrubs. Some people like to wrap shrubs, especially leafy evergreens (daphne, hebe, etc), with burlap or frost blanket during periods of very severe weather, and this can help somewhat if the cold snap doesn't last too long. Do not keep wrap on plants all winter, it can encourage rot.

Finally, you can avoid the temptation to grow half-hardy plants, meaning those plants that sometimes but don't always survive our winters.

For plants in containers, place the container in a semi-sheltered location for the winter. Some people like to go to the extra work of moving their containers to a garage or basement before a severe cold spell. If you go to the trouble, you need to move the plants out again after the cold spell has definitely past; don't leave the plants in such a place all winter.

Also, keep in mind that snow acts like a blanket for dormant plants. If the air temperature is way below freezing then the plants will actually be warmer under snow than if they are exposed to the air (think igloo heating).

These guidelines apply to plants that are capable of surviving the winter here in the first place and are not applicable to tender perennials and shrubs. For more information on winterizing tender plants, see our Gardening Solutions.

BACK TO TOP


"What types of cover crop do you have, and what can I still use in November?” November 2010

We sell about 9 different types of cover crop seeds. Most are either types of ryegrass, or members of the legume family (beans, peas, etc). The only exception is oilseed radish, with is marketed as being especially useful for helping to break up dense soils. Legumes generally are fast growing and cover a fair amount of space, and have the additional bonus of fixing nitrogen into the soil for future plantings to use.

The rye grasses, especially fall cereal rye, can usually germinate at quite low temperatures and might be the best choice for this late in autumn. We do sell a mixture of several plants called gardenway mix. With most cover crops, you want to turn them back into the soil in spring, a few weeks before you will be planting your spring. With many types it is at least as important to turn them in before they can go to seed, as they can become summer weeds otherwise.

See our handout on Cover Crops

BACK TO TOP


"This plant is widespread in an area that I want to make into a planting bed. It's cute, but seems to be quite an aggressive spreader. What is it, and how should I best deal with it?" Early April, 2011

CalthaThese are 2 different forms of the genus Caltha, probably belonging to the species C. palustris. They are widespread weeds that can form a thick mat in our moist, clay-based soils.

CalthaIt is a difficult plant to fight, as small pieces of root often fall back to the soil upon removal, and these roots can resprout quickly. Sprayable herbicides are not very effective this time of year, as they require some heat to work. Thorough and methodical removal of the roots is the best way to deal with this weed; it takes quite a bit of patience.

BACK TO TOP


"Can you identify this flowering shrub that I see in color around town right now, and tell me what I need to know about growing them?" Early April, 2011

Flowering QuinceThese are close-up pictures of the Chaenomeles speciosa, or flowering quince. They put on a spectacular bloom once a year in March to April, blooming before or just as the leaves come out. These are very hardy and reliable shrubs, basically growing themselves once established. They are well adapted to clay soil, but adding compost when planting a new one is of course a good idea. Most forms can get a few feet tall and several feet wide as a multi-stemmed shrub. Note that these grow suckers and can spread out. Oh yeah, and watch out; they have thorns!

BACK TO TOP


"My New Zealand flax turned black this winter, is it dead?" Early April, 2011

Phormiun tenax, or New Zealand flax, is an evergreen perennial with sword-shaped leaves that often has dramatically bright red, green, or yellow leaves. They are generally considered to be winter hardy and evergreen in our climate, but during harsh winter storms the leaves sometimes turn black and fail, rendering the plant… well, not evergreen. At that point the roots may or may not grow back in spring. My experience, so far, is that they usually do grow back, but quite slowly. Wrapping the plants with burlap or bubble wrap during severe dips in temperature can help to insulate and protect the plant if the freeze does not last too long.

BACK TO TOP

"My plums and blueberries sprouted out, but then the new growth and blossoms died off, and some of the branches are dying back. What is going on?" Early May, 2011

We have seen several samples of what appears to be blossom blight, being some species of fungi called Monilinia. It causes withered new shoots and some twig or branch loss on blueberries as well as cherries, plums, and other Prunus species. The disease usually happens to plants that are already under stress. It occurs when the air-borne fungus is present, the temperatures are moderate, and the leaves/blossoms are moist. Basically I just described Portland in spring. It can be deterred by pruning out effected branches or fruit in summer, using only moderate amounts of nitrogen fertilizer, and cleaning up thoroughly after autumn leaf fall. There are fungicides that are available to help control the problem if sprayed during and just after blossom.

BACK TO TOP


"My star jasmine looks really damaged right now, what happened and what can I do about it?" Early May, 2011

Trachelospermum jasminoides (Star Jasmine) is an evergreen vine but in our climate sometimes it takes damage to the leaves and possibly the stems during extremes of winter weather. In short, it doesn't always look especially good in spring time. Feel free to remove any dead or very ugly leaves and check to see which stems are alive or not. To do this, peel small bits of the bark back to check whether to stem has a green layer of tissue under the bark. If this is present, the stem is alive regardless of whether there are leaves on it are or not. Remove any dead stems and do any pruning of living stems that you think will make it grow back looking better; note that this pruning is not necessary. Finally, fertilize the plant and it should be looking good by mid-summer.

BACK TO TOP


"You don't have any carrot starts in your vegetable section. I can grow them now, right?" Early May, 2011

May is a fine time for starting carrots. We often do not have starts for these and some other root vegetables because it is often better to grow them from seed. This is also true of other members of the carrot family as well as radishes and, to some degree, beets. When growing these root crops ensure consistent and moderate soil moisture and use soils that have a somewhat high organic matter content and no rocks or pumice.

BACK TO TOP


"What is the deal with the grated tomatoes? I heard they are better somehow, but they cost more?" June, 2011

Tomato varieties with desirable fruit can be grafted onto the root system of another tomato that has superior vigor and disease resistance. This results in a plant that defends better against pests, diseases, and temperature extremes while producing earlier and more abundant harvests. This technique has been fairly unknown in our neck of the woods, but the method is used more commonly worldwide. More locals are now hearing about it and we can hardly keep our shelves full.

When planting the grafted tomatoes, do NOT bury the graft. Many gardeners have traditionally buried the stem of tomatoes to produce more roots early on, but you do not do that with grafted tomatoes. Handle the plant gently, and note where the graft is so that it is above the soil. As the plant grows, remove any side shoots that form below the graft, as those will not be the type of fruit that you wanted.

BACK TO TOP


"Highlighted problems occuring with this year's Fruit Trees" June, 2011

This spring has practically been a repeat of last year with frequent showers continuing well into June. For that reason, many of our fruit bearing trees have been heavily affected by leaf affecting fungal diseases. Here are highlights of some of the most common problems. As generalizations for cultural control, try to avoid overhead irrigation or unnecessary wetting of leaves, and give all fruit trees as much direct sun as possible. Do not crowd fruit trees with other large shrubs or trees. The gardener can apply fungicides to control the spread of the diseases. Some such products should be applied before the growing season starts and can only be planned for later on, and some fungicides are for use in the growing season to halt the spread of the disease. Feel free to use a web search for pictures of the ones mentioned below, and contact us for fungicide recommendations.

"My nectarine tree has weird, curly growth on the leaves, and most of them are distorted in this way. What is going on?"

This is peach leaf curl, also called Taphrina deformens or possibly a related species. It can also affect apricots and of course peaches.

"My pear tree has little brown spots on the leaves. It didn't seem serious at first, but it is spreading now to many of the leaves."

This is probably apple scab, and it also affects apples and crabapples. It will also leave growths on the fruit that resemble scabs. The fruit is edible but not pretty.

"There are little random holes in the leaves of my flowering plum. Is something eating it?"

This is not an insect, it is shothole fungus or coryneum blight. It is a fungus that affects cherries, plums, laurels, apricots, and other members of the genus Prunus.

BACK TO TOP

 

 

Plant Brochures

Annuals and Perennials

When can I find summer bloomers?

What summer blooming perennials can I plant?

Grasses

Should l cut back my ornamental grass?

What grasses can I grow that are evergreen?

What is that lovely grass (Fountain Grass)?

Bulbs and Seeds

Why don't my tulips come back every year?

When do fall bulbs arrive?

Fruits, Nuts and Berries

What can I do about worms in my apples?

Why is the new growth on my apples curly?

What are the weird spots on my grape leaves?

My plum leaves are curling

What amendments for planting blueberries?

Are bananas hardy?

My apple tree is almost ripe and ready to pick. Should I prune it right afterward?

Highlighted problems occuring with Fruit Trees

Houseplants

What houseplants continue to flower in my house?

What houseplants are easy to keep alive?

What indoor plants can I use with lower lighting?

Lawns and Groundcover

What can I do about the mushrooms in my lawn?

What can I do about all the clover?

What groundcover works under big fir trees?

When should I seed my patchy lawn?

What can I do about my patchy lawn?

What are these ugly moss-like things growing in my yard?

Roses

What are these black spots on my roses?

What are the fuzzy spots on my roses?

When can I move my rose bush (or other shrubs)?

Shrubs and Vines

Why aren't my hydrangeas blooming?

Do I need to plant two blueberry bushes to get fruit?

Which shrubs are fast-growing for screening?

What summer blooming shrubs can I plant?

Tell me about the Exbury Azaleas in bloom

Types and care for hydrangeas?

Are hibiscus hardy?

What is the brilliant red bush ?

What is a re-blooming lilac?

Tree Solutions

What should I know about the Crape Myrtle?

What is the great smelling tree (Clerodendrum)?

What are the 2" trees the city wants me to plant?

What tall evergreens are good for shade?

What are the common Cornus (Dogwood) varieties?

What is happening to my Cypress trees?