The leaves could be mistaken for the invasive English Holly - Oregon Grape’s resemblance to this plant gave it the scientific name Mahonia aquifolium. English Holly is Ilex aquifolium, and aquifolium means “leaves that have curved hooks like an eagles beak.” The 7-9 leaflets grow in pairs along a tough stem and are a glossy green with spines at the edges.
The grayish bark on the stems conceals a bright yellow inner bark that gets its color from the compound berberine. Botanists have argued over the years about whether to call the species Mahonia or Berberis - currently the Berberis camp is losing. Native peoples used the shredded bark to make a bright yellow dye for coloring basketry materials. The bark and berries were also used medicinally for liver, gallbladder, and eye problems, and the Cowlitz used an infusion of the bark as a wash for skin sores. The Quinault took a decoction of the roots for coughs, and according to the book Plants of the Pacific Northwest Coast “One Saanich woman noted that eating the berries in quantity was the only antidote known for shellfish poisoning. Great caution was used, because this drug is very potent.”
The berries are edible but were generally not eaten in quantity and were often mixed with Salal or some sweeter fruit. They contain large seeds and are rather sour. Some people make jam out of them, and I’ve read that some people ferment them into wine.
As this plant is the state flower of Oregon, I also think it bears pointing out that the bright green of the leaves and yellow of the flowers perfectly matches the sports jerseys of Oregon State University. Go Ducks!
Resources:
https://www.nps.gov/articles/000/oregon-grape.htm
https://www.uwb.edu/wetland/plants/mahonia-aquifolium
http://nativeplantspnw.com/tall-oregon-grape-mahonia-aquifolium/
https://www.wnps.org/blog/tall-oregon-grape-mahonia-aquifolium