Common Buckthorn

Common Buckthorn is a fast-growing, invasive shrub that forms dense thickets and crowds out native vegetation.
Rhamnus Cathartica
Origin: Europe/ Western Asia
USDA Hardiness Zones: 3-7
Pros:
Tolerant of poor soils – thrives in a wide range of conditions
Fast-growing – quickly establishes in disturbed areas
Cons:
Aggressively invasive – outcompetes native plants, forming dense thickets
Allelopathic – releases chemicals that hinder nearby plant growth
David Kim