Family: Berberidaceae (barberry family)
Height: 30 cm to 3 m (1 to 9.8 ft)
Berberis aquifolium Pursh
Stems: brown with a gray tinge on mature stems. Light brown with a light red and gray tinge on newer stems.
Flowers: clusters of 30 to 60 small, six-parted, yellow flowers which bloom in the spring. The flower head is a full inflorescence that can be up to 10-11 cm (4 inches) tall as they entice pollinators to visit.
Leaves: evergreen, alternately arranged along the stem. The leaves have five to nine leaflets with sharp, short spines on the leaf's teeth.
Fruit: large, juicy blue berries.
Sun: full sun to filtered shade
Ideal Conditions: filtered shade, open woodlands
Synynom: Mahonia aquifolium
Although it has been reported to have a low weed potential, Oregon grape has been problematic in natural areas including the Barker Woods Nature Preserve in Michigan City, the fragile ecosystem of the pannes in the Indiana dunes, and on the Indiana dunes in the Jack Pine stands. It is praised for its gorgeous yellow flowers, evergreen holly leaves, and shade tolerance. Its close sister species, Berberis repens (creeping barberry), has also been known to escape cultivation.
The differences between creeping barberry and Oregon grape are
1. B. repens creeps keeping a shorter height while B. aquifolium can grow considerable tall, and
2. B. repens underside of the leaves are bumpy whereas B. aquifolium's leaves are smooth underneath.
Another look-alike is the American Holly (Ilex opaca) which has alternately arranged leaves that are not on leaflets as seen in the Oregon grape. The top of the leaves are usually more shiny in the winter than on Oregon grape (see picture below). The American Holly is not native this far north.
It is native to the northwestern United States and not native to northwest Indiana. It is the state-flower of Oregon.
A yellow dye can be made from its roots and stems.
Unlike other barberries, Oregon grape is not susceptible to stem rust (Puccinia graminis).