Tall Oregon Grape (Mahonia Aquifolium)

It is the time of year, in early February, that I begin to welcome the sight of emerging buds of the state flower of Oregon: Mahonia aquifolium.  In a few week's time, all across the Pacific Northwest, tall Oregon grape will put forth bright, yellow masses of fragrant flowers that last for weeks starting at winter's end and lasting well into spring, making it an excellent source of pollen and nectar for early foraging native pollinators.

Mahonia aquifolium

Arthur R. Kruckeberg (1989) writes, "The showy bloom in early spring is confined to the tips of the canes.  The large clusters of smallish golden yellow flowers set on the lustrous green foliage are a glorious sight" (p. 101).  Pollinator activity will lead to an abundance of dusky bluish berries (not grapes, as its name implies), which support our native birds throughout the summer months.  Most years, our Oregon grape is stripped bare of its berries by summer's end, as these nutritious berries are much-loved by wildlife.  The berries are edible for humans, though quite tart, and are usually used to make jams or mixed with sweeter berries for a more palatable flavor.

I think tall Oregon grape looks best when grown along a hedge, though we have one as a centerpiece within our backyard habitat.  We let ours get tall and leggy, as wildlife usually benefits from native plants left in their natural form, and I think the branches look so pretty as they reach for the sun.  Always consider the mature size of the plant when planting.  Rhizomes spread close to the surface of the soil, so if desired, are easily removed, and can be propagated into new plants or shared with others.  This species is very easily propagated by seed as well.  If you're looking to enhance your backyard habitat, this species is native to most counties of the Pacific Northwest, and is highly supportive to wildlife year round.  See below for more details:

Native Habitat and Range:  "Moist to rather dry or rocky wooded slopes and thickets at low to mid elevations, from southern British Columbia south to California, and from the coast east through the Columbia River Gorge to eastern Washington, northeastern Oregon, northern Idaho, and Montana" (Robson, et al., 2008, p. 436).  As you can see, tall Oregon grape is found in a variety of areas from sunny slopes to the partly-shaded understory and moist to dry sites.  It usually thrives in sun.   

Size and hardiness:  5-8 ft. and just as wide with some branches reaching up to 10-12 ft. on mature stands.  Will eventually spread to form a hedge.

Propagation:  Rhizome cuttings,  hardwood cuttings in spring, or by seed.  Cold stratification over winter for spring germination.

Plant associates: Mixed conifer forests, Osoberry, vine maple, Pacific rhododendron, oceanspray, Oregon oxalis, salal, western sword fern, black twinberry, Pacific ninebark, evergreen huckleberry, and many others.

Ethnobotany:  Indigenous tribes and people groups used Mahonia aquifolium in a wide variety of ways from numerous medicinal uses to raw/preserved food and dyes.  You can read about how different tribes utilized this plant in different ways at Native American Ethnobotany DB.

Support to wildlife:  Attractive and supportive to pollinators as a late winter/early spring bloomer.  Berries attractive to a wide variety of native birds and small animals.  Foliage used by browse species and as cover for small animals, made especially protective by its spiny leaves.  

References

Kruckeberg, A. R. (1989). Gardening with native plants of the Pacific Northwest. University of Washington Press.

Robson, K. A., Richter, A., & Filbert, M. (2008). Encyclopedia of northwest native plants for gardens and landscapes. Timber Press.



 

 

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