About the Shrub Mahonia
Mahonia are native plants that grow profusely throughout the Pacific Northwest. Mahonia species also grow in other regions of the United States as well as China and Japan. Outside of Oregon they are often called grape holly due to their thick-spined leaves and blue berries. They are a tough, easy-care plant that will naturalize well in the right conditions.
Pacific Northwest Mahonia
There are three Pacific Northwest Oregon grape species. The most common is the Tall Oregon Grape (Mahonia aquifolium), which can easily reach 6 feet tall. Two lower-growing Northwest mahonias spread by underground stems. Longleaf Oregon Grape (Mahonia nervosa) is a small shrub (2 feet tall) that has a very long set of leaflets and a fern-like form. Creeping Oregon Grape (Mahonia repens) is only 1 foot tall and has bronze-red fall foliage. All three are very durable useful plants. Other attributes are the yellow fragrant flower clusters in the spring.
Fortunately, some mahonias from Arizona, Texas and Mexico will grow in warmer regions. One unusual species is Mahonia trifoliolata, which has orange to red berries instead of the traditional blue. This one has wavy leaves and handles dry hot conditions. Nevin Mahonia (Mahonia nevinii), which has red berries and thin, serrated leaves, is native only to California. Shiny-leaved Mahonia (Mahonia pinnata) is applauded for its very shiny leaves. Desert Mahonia (Mahonia freemontii), which grows in the Mohave Desert, has fat spined leaves with prominent veining. Desert mahonia stands out from the others due to its yellow berries.
Chinese and Japanese Mahonia
The Chinese version of the common Oregon grape has very different features. Chinese Mahonia (Mahonia fortunei) has leaves that are more fern or bamboo like. The foliage is not thick and spiny but is delicate and gray green. The low growing Chinese Holly Grape (Mahonia lamariifolia) is more reminiscent of the lower growing Oregon grapes. Leatherleaf Mahonia, (Mahonia gracilipes) is a highly ornamental Japanese species. The most unusual feature is its racemes of red flowers with yellow centers. The berries are larger than most and not as bitter.
Most mahonias are not fussy about soil type. They prefer some afternoon sun protection which can be achieved by planting them underneath trees. These plants require little water but will look better watered during very hot periods. Pruning is not necessary but the larger species such as the Tall Oregon Grape can be clipped shorter if desired. Remove dead or damaged leaves each spring to keep them looking good. If the soil is rich in organic matter there is no need to fertilize.
Oregon Grape has a bright yellow inner bark that makes a great dye. Native Americans used this yellow dye and also made a purple dye from the berries. They also used the berries as a food source which is continued today. Oregon grape wine and jelly are both made from the juice. The flavor is good but bitter, so the recipes usually require a lot of sugar. Birds really like the berries, so this alone is a good reason to grow them. Mahonia contains an alkaloid berberine, which has anti-inflammatory and anti-bacterial properties but should only be used by experts in botanical medicine.
Older horticulture books may list Oregon grape and other mahonia species as berberis. Sometimes the common name for mahonia is also listed as barberry. This is because they are both from the berberis family and are very closely related. For this reason the name has been changed back and forth through the years. As of now, botanists are content in calling these shrubs mahonia.
- Sunset Western Garden Book, Sunset Books, 2007