Butterfly bush (Buddleja davidii)
Other common names
Perennial shrub, flowers mid to late summer. Grows up to 10 feet tall. Leaves are narrow, opposite and green to blue-gray. Flower heads are lilac-like but come to a more definite point. Flowers are small and purple.
This plant is a pioneering species that dominates open habitats. It poses an ecological threat to dryland meadows, open slopes and dunes, dominating these sites as much as Scotch broom has historically. It also invades reforested sites, resulting in a loss of forest productivity.