Berberis aquifolium, theOregon grape[2] orholly-leaved barberry, is a North American species offlowering plant in the familyBerberidaceae. It is anevergreen shrub growing up to 3 metres (10 ft) tall and 1.5 m (5 ft) wide, withpinnate leaves consisting of spiny leaflets, and dense clusters of yellowflowers in early spring, followed by dark bluish-blackberries.
Berberis aquifolium grows to 1–3 metres (3+1⁄2–10 feet) tall[3] by 1.5 m (5 ft) wide. The stems and twigs have a thickened, corky appearance. Theleaves are pinnate and up to 30 centimetres (12 inches) long, comprising spiny leaflets. The leathery leaves resemble those ofholly. The yellow flowers are borne in dense clusters3–6 cm (1+1⁄4–2+1⁄4 in) long in late spring. Each of the sixstamens terminates in two spreading branches. The six yellow petals are enclosed by six yellowsepals. At the base of the flower are three greenish-yellowbracts, less than half as long as the sepals. The spherical berries are up to1 cm (3⁄8 in) wide,[2] dark dusty-blue, and tart in taste.[4][5]
Some botanists continue to place part of the barberry genusBerberis in a separate genus,Mahonia.[7][8][9][10] Under this classificationBerberis aquifolium is namedMahonia aquifolium.[11] As of 2023Plants of the World Online (POWO) classifies it asBerberis aquifolium with no valid subspecies.[1]
Berberis aquifolium is not closely related to either the true holly (Ilex aquifolium) or the true grape (Vitis), but its common name,Oregon-grape holly comes from its resemblance to these plants.[13]
The yellow flowers are pollinated byBombus species, amongst other insects.
As with some otherBerberis,B. aquifolium can serve as analternate host forwheat yellow rust (Puccinia striiformis f. sp.tritici, which usually preferswheat), but it is unknown whether this occurs naturally.[14]
In some areas outside of its native range,B. aquifolium has been classified as an invasiveexotic species that may displace native vegetation.[15][16]
Berberis aquifolium is a popular subject in shady or woodland plantings. It is valued for its striking foliage and flowers, which often appear before those of other shrubs. It is resistant to summer drought, tolerates poor soils, and does not create excessiveleaf litter. Its berries attract birds.[17]
The small purplish-black fruits, which are quite tart and contain large seeds, are edible raw[21] after the season's first frosts.[22] They were included in small quantities in the traditional diets ofPacific Northwest tribes, mixed withsalal or another sweeter fruit. Today, they are sometimes used to make jelly, alone or mixed with salal.[23] Oregon-grape juice can be fermented to make wine, similar to European barberry wine folk traditions, although it requires an unusually high amount of sugar.[24]
The inner bark of the larger stems and roots of Oregon grape yield a yellow dye. The berries contain a dye that can be purple,[25] blue, pink, or green depending on the pH of water used to make the dye, due to the berries containing a naturally occurring pH indicator.[original research?]
^"Landscape Plants: Mahonia aquifolium".Oregon State University: College of Agricultural Sciences - Department of Horticulture. Oregon State University. Retrieved4 July 2020.
^Loconte, H., & J. R. Estes. 1989. Phylogenetic systematics of Berberidaceae and Ranunculales (Magnoliidae). Systematic Botany 14:565-579.
^Marroquín, Jorge S., & Joseph E. Laferrière. 1997. Transfer of specific and infraspecific taxa fromMahonia toBerberis. Journal of the Arizona-Nevada Academy of Science 30(1):53-55.
^Laferrière, Joseph E. 1997. Transfer of specific and infraspecific taxa fromMahonia toBerberis. Bot. Zhurn. 82(9):96-99.
^Lyons, C. P. (1956).Trees, Shrubs and Flowers to Know in Washington (1st ed.). Canada: J. M. Dent & Sons. p. 196.
^Pojar, Jim; MacKinnon, Andy, eds. (1994).Plants of Coastal British Columbia: including Washington, Oregon & Alaska, rev. ed. Vancouver: Lone Pine Publishing. p. 95.ISBN978-1-55105-532-9.
^Henderson, Robert K. (2000).The Neighbourhood Forager. Toronto, Ontario: Key Porter Books. p. 111.ISBN1-55263-306-3.
^Bliss, Anne (1993).North American Dye Plants, rev. and enl. ed. Loveland, Colorado: Interweave Press. p. 130.ISBN0-934026-89-0.
