Berberis aquifolium, the Oregon grapeorholly-leaved barberry, is a speciesofflowering plant in the family Berberidaceae, native to western North America. It is an evergreenshrub growing 1–3 meters (3–10 feet) tall and 1.5 m (5 ft) wide, with pinnate leaves consisting of spiny leaflets, and dense clusters of yellow flowers in early spring, followed by dark bluish-black berries.[2]
The berries are included in the diet of some aboriginal peoples of the Pacific Northwest, and the species is recognized as the state flowerofOregon.
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. The leaves are pinnate and up to 30 centimetres (12 inches) long, comprising spiny leaflets. The leathery leaves resemble those of holly. The yellow flowers are borne in dense clusters 3–6 cm (1+1⁄4–2+1⁄4in) long in late spring. Each of the six stamens terminates in two spreading branches. The six yellow petals are enclosed by six yellow sepals. At the base of the flower are three greenish-yellow bracts, less than half as long as the sepals. The spherical berries are dark dusty-blue and tart in taste.[4][5]
Some botanists continue to place part of the barberry genus Berberis in a separate genus, Mahonia.[7][8][9][10] Under this classification Berberis aquifolium is named Mahonia aquifolium.[11] As of 2023 Plants of the World Online (POWO) classifies it as Berberis 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 by Bombus species, amongst other insects.
As with some other Berberis, Berberis aquifolium can serve as an alternate host for Wheat yellow rust (Puccinia striiformis f. sp. tritici; the primary hostofPst being wheat). However, in B. aquifolium this was only achieved by intentional inoculation in a lab, and it remains unknown whether this occurs naturally.[14]
In some areas outside its native range, Berberis aquifolium has been classified as an invasive exotic 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 excessive leaf litter. Its berries attract birds.[2]
The small purplish-black fruits, which are quite tart and contain large seeds, are edible raw[20] after the season's first frosts.[21] They were included in small quantities in the traditional diets of Pacific Northwest indigenous peoples, mixed with salal or another sweeter fruit. Today, they are sometimes used to make jelly, alone or mixed with salal.[22] 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.[23]
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,[24] 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?]
^ abRHS A-Z encyclopedia of garden plants. United Kingdom: Dorling Kindersley. 2008. p. 1136. ISBN978-1-4053-3296-5.
^"Landscape Plants: Mahonia aquifolium". Oregon State University: College of Agricultural Sciences - Department of Horticulture. Oregon State University. Retrieved 4 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 from MahoniatoBerberis. Journal of the Arizona-Nevada Academy of Science 30(1):53-55.
^Laferrière, Joseph E. 1997. Transfer of specific and infraspecific taxa from MahoniatoBerberis. 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.
