Frangula alnus Mill.
Rhamnus frangula L.
- Moss, Flora of Alberta – No
-  Global Invasive Species Database – Yes
- NatureServe I-Rank – High/Medium
- AB Weed Act status – ?
"...can grow to seven metres and is sometimes considered a tree. Frangula alnus typically inhabits wet, shaded and acidic soils. It can grow in soils of any texture. In North America, wetlands are invaded by Frangula alnus. Frangula alnus is also a typical woody pioneer during the succession of drained mires and conveyed wet meadows, being overgrown and substituted by forest vegetation. The invasion of Frangula alnus into forests and riparian areas in the North American region has alarmed foresters and conservationists..."
"...Buckthorns rapidly form dense, even-edged thickets followed by lateral crown thread which continues until branches touch adjacent shrubs forming continuous canopy and creating dense shade that eliminates native tree seedlings, saplings, and ground layer species. Heavy infestations decrease the total cover and alter the species dominance of the herbaceous layer in riparian savanna. Other woody species experience negative effects on growth and seedling establishment. Although fairly widespread in the United States, particularly the eastern half, the species continues to spread into open and semi-open woodlands, but also into some upland woodlands..."
 Link to Wikipedia, Rhamnus frangula - "...probably introduced to North America about 200 years ago, and in Canada about 100 years ago. It was planted for hedgerows, forestry plantings, and wildlife habitat, but has become an invasive species, invading forests in the northeastern United States and wetlands and moist forest in the Midwestern United States. It is predicted to continue to expand its North American range..."
 Link to USDA Plants, Profile and map for Frangula alnus Mill., glossy buckthorn