The Oregon grape (Mahonia aquifolium), was designated the Oregon state flower in 1899. Also called hollyleaved barberry , the Oregon grape is a shrub native to much of the Pacific coast and and is also found sparsely east of the Cascades. Its year-round foliage of pinnated, waxy green leaves resembles holly.and resists wilting (the foliage is sometimes used by florists for greenery).

The Oregon grape plant bears dainty yellow flowers in early summer and a dark blue berry that ripens late in the fall. The fruit is tart and bitter, containing large seeds, but can be used in cooking (used to make jelly locally). The inner bark of the larger stems and roots of Oregon grape can be used to make a yellow dye.

Oregon grape root is commonly used medicinally by herbalists as an effective anti-inflammatory and anti-bacterial used in the treatment of infection. Oregon grape root also has anticancer properties and is used for treating inflammatory skin diseases such as Eczema and Psoriasis.

Source:

State Flower: Oregon Blue Book
Oregon-grape: Wkipedia.org

Links:

State Seals - 50 States List
National Seal