The Oregon Grape Mahonia is upright, somewhat suckering and usually forms a dense, rounded clump. It is generally smaller and denser than 'Charity' or Leatherleaf Mahonia. It has glossy, dark green, compound leaves with very spiny, holly-like leaflets. In cold weather, the leaves often turn attractive shades of bronze, maroon, or reddish-purple, providing excellent winter color. Clusters of bright yellow, fragrant flowers appear at the tips of the branches in early to mid-Spring. Showy clusters of grape-like, powdery blue-black berries ripen in summer, highly valued by birds.