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white bryonia (Bryonia alba)
ODA rating: A

Other common names
white bryony, wild hops, devil's turnip, and western kudzu

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Images courtesy of Rich Old, XID Services. 
If images are downloaded and used from the ODA web site please be sure to credit the photographer.

White bryonia is a vigorous herbaceous perennial vine resembling kudzu in appearance and growth habit. Infestations will overgrow and smother small trees and shrubs forming dense mats which shade out all the vegetation it grows upon. If established in areas with no structure to climb, it will form a dense mat covering the ground. Vines emerge each spring from a large fleshy parsnip-shaped tuber and grow rapidly, sometimes to 30 feet in a season. White bryonia develops a herbaceous vine each year sporting tendrils and palm-shaped, alternate, broadly five lobed leaves which are covered on upper and lower surfaces by small white glands. Flowers are small, greenish-white, with five petals and produced in clusters. Fruits consist of dark-blue berries that can be 5/16 inches in diameter when fully ripe. When crushed, the berries contain a viscous fluid and emit a very bad odor. While the plant leaves and vines resemble the native Marah oregana, the fruiting structure on the native cucumber is a golf-ball sized fleshy pod covered in soft pointed outgrowths, very unlike the black berries of the invasive species. The plants do not overlap in their growing environment. Reproduction occurs both sexually by seeds and asexually by apomixis. Population studies indicate multiple introduction events in the Pacific Northwest resulting in large clonal populations produced through apomictic production of propagules (Mack & Novak 2000). Some genetic variation is occurring through cross pollination between clones. For long-distant dispersal, blue-black seeds are produced which are eaten by birds and deposited after digestion.

All parts of the plant contain byonin which is poisonous to humans. Poisoning cases have been reported from this and related species worldwide. Livestock are also poisoned by eating the leaves and fruit. Dried root powder derived from the tubers is used in herbal medicine treatments and sold on many websites. White bryonia aggressively climbs and smothers small trees and shrubs commonly found along riparian areas and springs. Thick mats will exclude all other vegetation wherever it establishes in good soil. Many important geographic areas are at risk especially Hells Canyon and other river canyons of the Pacific Northwest where it can be expected to compete with native plants which often provide browse for game animals. Control and removal costs currently represent the largest economic cost to white bryonia invasion. Vines can present a problem in yards, fencerows on farms and in parks. Control is difficult and often takes several years.
This plant is native to Europe and northern Iran. It has been documented in the United States in Montana, Nez Perce and Latah counties and in Idaho as well as the SE counties of Washington State. Report indicate that it is spreading rapidly in all areas.

Distribution in Oregon
This plant is not known to be present in Oregon at this time.

Biological controls
Biological control agents are not used on "A" listed weeds in Oregon. If found this weed will be managed for eradication.
Informational links:
Oregon WeedMapper