Mahonia nervosa and Mahonia aquifolium
Both varieties of Oregon grape are common in Puget Sound urban forests. They are evergreen shrubs and important understory species. Their leaves look somewhat like holly to the untrained eye, however, compound Oregon grape leaves are thinner and more delicate than those of the holly. Holly leaflets are shaped slightly differently, and are much thicker and pricklier. Both species of Oregon grape are true shrubs, and never grow to be trees like holly. They have small yellow flowers in the spring and blue-purple berries in late summer.
Dull Oregon grape is smaller in size at 1′ -2′. Its leaves have between nine and nineteen leaflets, which are thin and lighter green. The Tall Oregon grape has five to nine dark, shiny leaflets per leaf, and grows 3′ – 10′ tall.