MAHONIA: Oregon Grape
Here's another one of those taxonomy debates – is it Mahonia, or Berberis? You will find it listed both ways, but either way, it is still Oregon grape, one of the most common (and therefore frequently overlooked and underappreciated) of our native shrubs - the official State Flower of Oregon.
Of the many species of Mahonia (Berberis), three are abundant in Oregon and throughout the Pacific Northwest: M. aquifolium, M. repens, and M. nervosa. All three are evergreen and have the characteristic holly-like leaf shape, some more pointed and prickly than others. Woody-stemmed and spreading by rhizomes, the new growth in the spring emerges in a light green to soft coppery-red color; at the other end of the year the foliage responds to colder weather by taking on shades of bright red to burgundy - truly lovely in the grayed winter landscape. In mid-spring, the plant is topped with sprays of small bright yellow fragrant flowers in a long-blooming display that attract bees, hummingbirds and other pollinators to the garden.
Following the bloom are clusters of dusky blue, round to oblong berries that are the "grapes" that give it its common name. The berries are edible, though not always palatable, as they are often quite tart. Recipes for jelly usually combine the juice of Oregon grape with that of the sweeter salal berries or apple concentrate. The root has traditional medicinal properties, and along with the yellow inner bark has been used as a dye. There are many sources of information about these uses but here are two at Bosky Dell Natives: Recipes from Bosky Dell Natives and an article by Judy Bluehorse Skelton, herbalist and educator (Thank you to Bosky Dell Natives).
In general, richly acidic, well-drained soil in partial shade suits these plants best. Because of their long roots, established plants usually don't survive transplanting very well. So site them where you want them to grow and thrive, and enjoy their beauty as well as the birds that will be attracted by the food and cover that all species of Oregon Grape provide.
Tall Oregon Grape
This woodland beauty is Oregon's state flower. It is the tallest of the native species, sometimes reaching up to ten feet, though more often in garden settings staying four-to-five feet tall; upright, sometimes slightly arching branches covered with the prickliest of leaves – a good candidate for a hedgerow or back of a garden bed.
Give it some space, for the tough rhizomes can have it spreading to a richly textured evergreen thicket that is a wonderful protective site for birds. The effects of cold, sun and even age, will cause leaves to take on shades of red to nearly purple, providing a rich tapestry of color when joined with the bronze-red color of its new growth, the bright yellow of the flowers and the dusky blue of the berries.
M. aquifolium can easily withstand the dry shade under large trees, though also tolerant of moist (not wet) conditions. It can grow in full sun, but will suffer if not given some shade where summers are hot, even with more regular water. All in all, a beautiful, adaptable, bird-friendly addition to many garden settings.
Cascade, Long-leaved, or Dull Oregon Grape
This Oregon grape is lower growing, spreading evergreen shrub, topping out at about two feet. The pale yellow flowers form in long racemes of about eight inches, and the leaves are longer and a grayer-green color than the M. aquafolium.
A slower-growing species, it is especially well-suited to areas of dry shade, providing an attractive anchor for the border of a shady garden. Cold weather will turn the leaves a rich wine color, and older leaves often turn a brilliant red before falling off.
Low, or Creeping Oregon Grape
The lowest growing of the three, M. repens generally grows to only about a foot in height, with a spread to three feet. The spines on the more rounded leaves are weaker, so not so dangerous to place near a path. A species from east of the Cascades, low Oregon grape will grow happily in full sun to full shade; it is the most successful for perpetually dry shade and once established is drought tolerant even in sunny conditions. Full sun and winter cold give the leaves a bronze cast. A great plant for cover and food for ground-feeding birds.
M. repens is considered a noxious weed in other parts of the country, but is fully garden-worthy here in its native range.
(There is a fourth native species, M. pumila - dwarf western Oregon grape - native especially to the far corner of southwest Oregon and into northern California. It is lower growing even than the M. repens, with blue-gray-green leaves, and is also tolerant of drier, sunnier conditions. It is not commonly available, however so M.repens is the usual choice for sunnier, drier garden settings)
Genus: Mahonia (Berberis)
Common: Oregon Grape
Native Range: One or more of the four native species of Mahonia can be found in almost every county in Oregon; common along the entire west coast and eastward toward the Rockies.
Characteristics: Evergreen woody-stemmed shrubs with distinct holly-like leaves. Bronze-colored new growth in spring, with mounds of small, bright yellow fragrant flowers in spring, followed by clusters of round, dusky blue (edible, though often sour) fruit. Foliage often takes on a striking red to purplish cast in fall-winter.
Culture: Grows best in partial sun - though some species can thrive in full shade to full sun - rich acidic soil, and to moist to dry conditions. Avoid planting Oregon grape in soil that is compacted, wet, or too alkaline; plants should also be protected from winter winds.
Pests/Diseases: Leaves can become chlorotic in soil that is too alkaline, and can suffer leaf-burn in winter winds. Occasionally some leaf spot in too-wet conditions, but virtually pest and disease free.