Butterfly bush

Genus: Buddleia

Species: davidii

Description: Deciduous or semi-evergreen shrub, large, 8-12 ft (2.4-3.7 m) high. Flowers small, fragrant, usually borne in spike-like slender, dense (10-25 cm long) terminal clusters, often lilac colored with orange at the opening. Blooms in summer, cultivated for ornamental purposes for its pretty flowers and ability to attract butterflies.

Where it grows: Rapidly colonizes bare or disturbed sites, natural forests, riparian zones, urban areas, water courses and wetlands.

How it spreads: Produces large quantities of extremely lightweight, winged seeds – up to three million per plant - that are dispersed by wind and water. These seeds can remain dormant in the soil for three to five years. This shrub can also reproduce vegetatively, as cut stems can sprout roots and grow into new plants.

What it threatens: Oregon Department of Agriculture recently placed Buddleja davidii on its list of B-class weeds; i.e., widespread invasive weeds that should be contained and controlled to prevent them from becoming major problems. Dense infestations of Buddleia compete with indigenous vegetation of rivers and impede the growth and reproduction of other species of trees and shrubs.

More information: 4 County Cooperative Weed Management Association

Disclaimer - Clean Water Services does not endorse or recommend specific herbicides for use in controlling these species. To protect water quality, always follow herbicide label directions and obey application laws when using any herbicide.