Washington Native Plant Society: Starflower Image Herbarium

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Mahonia aquifolium

Tall Oregon Grape

At a Glance: Erect, stiff-branched shrub with holly-like leaves and clusters of yellow flowers.

Height: 2.5 - 6.5 feet (0.8 meters - 2 meters).
Growth Form: Shrub.
Stems: Bark and stems are yellowish due to an alkaloid berberine.
Leaves: Leaves are alternately arranged, turn red/purple in winter, 5-11 leathery leaflets per leaf, leaflets are spiny toothed margins with a glossy topside and prominent red central veins; shape: oblong to elliptic; size: 8-24 cm (3-10 in) long.
Flowers: Many in erect clusters that are up to 20 cm (8 in) long, flower parts in sixes; primary color: bright yellow; size: about 0.5 cm (0.25 inches) long.
Flowering Period: April, May.
Fruits: Berries are 4-7 mm diameter, ovoid; dark blue with a white bloom; contain a few large seeds 4-5 mm long; flowers are born in an elongated cluster.


Photo © Heidi Bohan

Sun/Shade Tolerance	Hydrology	Elevation Range
More tolerant of open sites than Mahonia nervosa. full sun > 80% mostly sunny 60%-80% partial sun and shade 40%- 60% mostly shady 60%-80% full shade > 80%	More tolerant of drier sites than Mahonia nervosa. wet moist dry Wetland Indicator Status: NI (no indicator data)	Below 1200 meters elevation. low elevation mid elevation sub-alpine high elevation

Soil Preferences
Tolerant of nutrient-poor, rocky soils.
sandy soils gravelly soils clay soils muddy soils peaty soils	well drained soils shallow soils deep soils acidic soils basic soils	humic soils nutrient rich soils nutrient poor soils mineral soils organic soils

Habitat Preferences
Aquatic and Wetland: Ponds or lakes Shallow pools Sloughs Swales or wet ditches Seasonally inundated areas Marshes or swamps Aquatic bed wetlands Emergent wetlands Scrub-shrub wetlands Forested wetlands Bogs, fens Seeps, springs Shorelines and Riparian: Lake shores Bog margins Streams or rivers Stream or river banks Riparian corridors River bars Floodplains Bottomlands Alluvial areas	Saltwater Areas: In or near saltwater Mud flats Tidal areas Estuaries Saltmarshes Brackish water Seashores Coastal dunes or beaches Rocky or Gravelly Areas: Coastal bluffs Cliffs Rocky slopes Outcrops Crevices Glacial outwash Gullies Slide areas Sub-alpine and Alpine: Heaths Snow beds Tundra Avalanche tracks	Forests and Thickets: Forests and woods Open forests Coniferous forests Old growth forests Deciduous forests Mixed forests Nurse logs Forest edges, openings, or clearings Thickets Meadows and Fields: Pastures or fields Meadows or grassy areas Mossy areas Disturbed Areas: Roadsides Trailsides Logged sites Burned areas Disturbed sites

Wildlife Value
Berries Seeds Nectar for hummingbirds Nectar for butterflies Host for insect larvae Thickets and shelter Thorny or protective cover	Birds: The berries are eaten by many birds including grouse, pheasants, robins, waxwings, juncos, sparrows, and towhees. Insects: Orchard mason bees and painted lady butterflies use the nectar. Mammals: Foxes, raccoons, and coyotes eat the berries. Deer and elk will occasionally browse the leaves and flowers.

Ethnobotanical Uses and Other Facts

Food Uses: Fruits are edible.
Landscape Uses: Use as a hedge or individually; prune lightly.

Suggested References

Alden, P., D. Paulson. 1998. National Audubon Society, Field Guide to the Pacific Northwest. Chanticleer Press. Page 362.
Hitchcock, C.L., A. Cronquist. 1973. Vascular Plants of the Pacific Northwest. University of Washington Press. Page 142.
Jacobson A.L. 2001. Wild Plants of Greater Seattle. Published by author. Page 116.
Lyons, C., W. Merilees. Trees and Shrubs to Know in Washington and British Columbia. Lone Pine Publishing. Page 139.
Pojar, J., A. Mackinnon. 1994. Plants of the Pacific Northwest Coast. Lone Pine Publishing. Page 95.

The landscaping and restoration information provided on this page is taken from Starflower Foundation Image Herbarium. All photographs © Starflower Foundation unless otherwise noted.