AN HERB TO KNOW

Enlarge Image Image Gallery Photograph by J. G. Strauch, Jr.

Oregon Grape Mahonia aquifolium (Muh-HO-nee-uh ak-wih-FO-lee-um) Family Berberidaceae Hardy evergreen shrub

GOOD AUTUMN LEAF color, abundant clusters of yellow flowers, and blue-black, edible fruits have made this handsome, spiny-leaved evergreen shrub a widely promoted ornamental, especially in the American West. Less well known are its coloring and medicinal properties, which have long been used by Native Americans and others.

The genus Mahonia comprises seventy species of evergreen shrubs and small trees native to North and Central America and Asia. It was named for the Irish-born Philadelphia nurseryman Bernard M’Mahon, or McMahon (1775–1816), whose American ­Gardener’s Calendar (1806) was America’s first comprehensive, practical ­gardening book.

M. aquifolium is native to western North America from British Columbia to Northern California but is planted throughout much of the country. It grows to about 6 feet tall and 3 to 5 feet wide and spreads by suckers.

The glossy leaves are pinnately divided into five to thirteen leaflets, each of which resembles a holly leaf (aquifolium, which means “sharp-leaved,” is the Latin name for holly). Red-bronze when newly open, the leaves become dark green in summer, then purplish or bronze in fall and winter, particularly when planted in sun and where winters are cold.

The dense clusters of tiny flowers, which appear in March through May, are 2 to 3 inches long and slightly fragrant; they’re Oregon’s state flower. Grapelike berries 1/3 inch in diameter ripen in July through September and are the source of the plant’s common names, Oregon grape holly and Oregon holly grape.

Oregon grape may be used as a foundation planting, specimen shrub, or in a woodland setting. Hardy in Zones 4 or 5 to 8, it’s best grown in the shade in hotter climates and with protection from leaf-scorching winter winds in colder ones. ‘Compacta’ is a 2-foot-tall cultivar with foliage that starts out glossy light green and turns to a dull green in summer. For a ground cover, try 10-inch-tall creeping mahonia (M. repens), which has dull blue-green leaves in summer and smaller “grapes.” A number of other American and Asian mahonias are sold as landscape plants.