July Gardening Tips
As these days get hotter watch (and increase) watering, especially for containers and hanging plants. Remember with all watering, that deep, thorough watering is still more important than frequency.
Many vines start looking their best in summer including star jasmine, honeysuckle, climbing hydrangea, and passionflower. Regularly trim your established vines to keep them tidy and on their support structures. This can mean removal of some vines if a congested vine needs thinning or it can mean snipping off new growth for vines that are getting too long. For newer vines that are not yet grown in, regular doses of fertilizer can speed the process somewhat. Watch for powdery mildew on akebia and honeysuckle vines, especially if they are somewhat shaded.
Explore the wonder and beauty we have in Portland's many parks. Check out the Green Walks program through Portland's division of Parks and Recreation. Pick up a brochure at the nursery or call 503-823-3601 for more information.
Most summer blooming annuals are in full swing by now and they should be looking great if nothing is going wrong. Remove the seeds from fuchsias and dead head your petunias to encourage more flowers. Watch for slugs (of course) and caterpillar damage on annuals in general and geranium budworm on geraniums and petunias. This budworm can be identified by the small black frass on the leaves and ruined blossoms. Watch for powdery mildew on zinnias, showing as damaged leaves with a white powdery growth. Other than that, most annuals should be fertilized regularly to keep them growing and blooming and you can always add more throughout the season, we will have plenty.
Some perennials do not come into their best until July. This includes lilies, coreopsis, and most daisy-like plants such as coneflower, goldenrod, and shasta daisies. Hardy geraniums, many salvias, and scabiosa are examples of repeat bloomers that will keep going for a long while. The mallow family plants (hollyhock, hibiscus, and lavateras) are coming into bloom as well. Watch for the fungal hollyhock rust and treat promptly; it is a common disease.
Some of the taller growing perennials may require staking or some other support system as they grow. This includes dahlias, delphiniums, crocosmia, and some other upright spike-style flowers. If you are using a caging system such as a tomato cage or peony support cage it is best to have the cage in place before the plant is large. If you are staking individual stems then simply do so before they grow too tall and heavy to support themselves.
While we may have had some dry weather in June, July is usually the first month you have to do regular irrigating. How your flower beds need water can vary greatly. Recently planted annuals and perennials will probably require quite regular, even frequent watering. If they are side by side with established perennials or shrubs try to avoid excessive soaking of these established plants. If you prefer to irrigate the entire bed then do so thoroughly but only occasionally, giving extra drinks to the recent plantings as they need it. Some fresh mulch on top of the soil can help to conserve water.
Early cold season crops are coming to the end of their season. Harvest any peas you still have growing and harvest your spring batch of cole crops (broccoli, cabbage, etc.) as soon as they are ready if you have not already. Leafy greens should be harvested if they are near their full size, and new plants can be started by seed in part sun throughout the summer. These can be harvested as baby greens or semi-mature plants during hot weather to prevent bolting. Bolting is the process during which the plant goes to flower and seed and the flavor of the leaves turns bitter.
Late July or August are a good time to start a new round of cole crops for fall to winter harvest, especially Brussels sprouts which need a very long season to be ready. A fresh crop of greens for fall is perfectly doable, and peas often work out in autumn as well. If you are trying to figure out exactly when to start your fall crop, remember that it usually take about 14 days longer from germination to maturity than the spring crop does. To figure this, check the seed packet for 'days to maturity', add 14 days, and subtract from the average last frost date for your last recommended planting date. The average first frost in inner Portland is mid- to late November, but it can happen as early as late October. Outlying areas and higher elevations tend to have an earlier first frost date.
Example: A packet if lettuce seeds says 50 days to maturity. Add the 14 days and subtract from November 15th, and you get September 12th as your last recommended start date, 64 days before November 15th.
Most of your warm season fruiting crops should hopefully be already planted. This refers to tomatoes, peppers, cucurbits (squash, cucumber, etc.), and melons. If you have not done so, you can still plant short season crops such as cherry tomatoes and chili peppers from started plants. Corn can still be started in the first half of July.
Many short season root vegetables can be started now, such as turnips, radishes, and carrots. Some long season root crops may be nearing harvest time, particularly the onions and garlic. See our care sheets on onion culture and garlic for details on when and how to harvest.
As for your ripening summer crops, keep watering regularly. Note that this means watering before a plant is dry and dehydrated, it does not mean keeping plants in wet soil. Over- and underwatering are primary contributors to other problems such as fungal attacks and bloosom end rot. When you see signs of disease or pest problems take care of them as soon as possible to keep the impact upon your harvest minimal. As always, we can help to diagnose and suggest treatments for plant problems.
See our Vegetable page for all care sheets and planting guides.
Most of us are familiar with the basics of summer lawn care; mowing, watering regularly, and fighting those dandelions. Here are a few tips that may help a bit. Do not mow your grass low to the ground. This can stunt the grass while allowing more light to the weeds in amongst your lawn. Mowing at four inches high is generally a good starting point.
The old axiom on watering is one inch per week, watering only once per week. This works great for established lawns, but newly rooting seed or sod may need more frequent applications. Many people have their sprinklers set to engage every day or every other day and this is unnecessary and sometimes even detrimental as the goal is to water deeply to encourage downward root growth. As for those dandelions, we sell tools specifically for pulling them out root and all (well, hopefully all the root).
Also, regular applications of fertilizer and lime on a healthy lawn can help the lawn to simply outcompete some weeds. There are of course herbicides available for those who are not having success fighting weeds in other ways.
While there are many different pests and diseases that can affect lawns, there are no particular ones that are so common as to warrant attention here. If you see symptoms such as dead spots, unusual growth rings, or other strange symptoms feel free to check with us for a correct diagnosis and treatment.
Hebe, rose of Sharon (Hibiscus syriacus), Hydrangeas, and fragrant summersweet (Clethra spp.) start blooming and looking their best in the warm weather. Potentillas and Escallonia keep on blooming and crape myrtle (Lagerstromeia spp.) will be starting to flower now or in August. Most trees are out of bloom by July but some late dogwoods may still be showing color. Evergreen Magnolias and Stewartias are warm season bloomers and should be getting started. If you are not familiar with the latter, find a picture of their fabulous Camellia-like blossoms.
Your roses should be in full bloom at this point or re-growing after their first flush of flowers. Unfortunately, this is now the time when black spot and powdery mildew fungi start moving in. Remove diseased leaves, do not moisten leaves, and apply fungicide regularly to keep problems to a minimum.
As stated above in the perennials section, water your new plants regularly but not excessively. Avoid watering truly established shrubs and trees frequently as this can slowly cause overwatering and even plant failure. Occasional deep waterings and water after fertilizer application are generally the only irrigation established woody plants need.
Spider mites may make their first appearance now or in August. They are very small pests that thrive in hot, dry weather. Mites can affect a number of plants including several types of conifers such as arborvitae and spruce, roses, many fruit trees, and cane berries such as raspberries.
Some fruit plants are already ripe or close to ripe including strawberries and early raspberries and blueberries. Slugs can be a problem with strawberries so slug baits May through early July can increase your harvest. Other fruits, primarily fruit trees, are well in the ripening phase and some fertilizer can help the plants along if you have not done so recently.
Many fruit trees are subject to a number of fungal leaf-affecting diseases during wet spring weather. It might be a little late for treating such problems; the drier air of summer usually lets the trees put on a fresh flush of new growth. It still pays to know your enemy and we will be happy to diagnose any problems. Some sprays may still be appropriate such as treatment for powdery mildew on apples. More commonly, dormant sprays can be planned for this upcoming winter to prevent re-infections next year.
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