Rhamnaceae - buckthorn family
 

WeedsPoisonous PlantsHay Fever
Gerald A. Mulligan (Agriculture Canada, Ottawa, retired)
Rhamnus cathartica L., European buckthorn, nerprun cathartique
A many-stemmed bush from 6 to 15 feet (18 to 45 dm.) high; rarely a small tree up to 30 feet (90 dm.) high. Male and female flowers are on separate plants. Female plants produce clusters of small, round, black fruits with 3 to 4 seeds. Reproduction is entirely by seed. Seeds of mature fruit, with a very high germination rate, are spread widely in the droppings of birds. European buckthorn was introduced into this Continent, from Europe, as a hedge and windbreak plant and it is now locally common along fencerows, in waste places, and along the gently sloping banks of lakes, rivers, and streams. Although widespread, it is especially common in eastern North America. It can tolerate a wide range of soil and moisture conditions, and in some areas forms a dense carpet that can supplant all other vegetation. It is almost impossible to eradicate once established. Orange-colored aecia, the sexual alternate stage of the fungus crown rust of oats (Puccinia coronata), are frequently present on the underside of the leaves of European buckthorn. Spores from these aecia are capable of producing the destructive asexial stages on any nearby plants of oats. For this reason, growers rarely attempt to grow oats as a crop in areas where European buckthorn is common. New strains of crown rust of oats are continually being formed, during the sexual aecial stage of the rust, on leaves of European buckthorn. There are even recent reports of the production of new strains capable of infecting barley plants.

Click on a photo to view an enlarged image.
Weed Name Photo Weed Name Photo
European buckthorn, nerprun cathartique
(fruiting branch)
European buckthorn, nerprun cathartique
(fruiting branch)
European buckthorn, nerprun cathartique
(close up of fruit)
European buckthorn, nerprun cathartique
(F&M)
European buckthorn, nerprun cathartique
(bush/tree)
European buckthorn, nerprun cathartique
(herbarium specimen, young fruit)
European buckthorn, nerprun cathartique
(young plants)
European buckthorn, nerprun cathartique
(2 seedlings)
European buckthorn, nerprun cathartique
(alternate aecial stage of the fungus disease, Puccinia coronata, crown rust of oats, on a leaf of European buckthorn)