What is it?
The butterfly bush is a perennial, woody shrub with purple flowers. It is a very popular ornamental plant, often found in gardens. It also is common along riverbanks and river gravel bars where it out-competes native plants and alters soil nutrients.
Is it here yet?
Yes. Escaped, invasive populations of butterfly bush are pervasive in western Washington, including Clallam, Clark, Cowlitz, King, Lewis, Skagit, Snohomish, Thurston, and Whatcom counties.
Why should I care?
Butterfly bushes form dense, shrubby thickets that exclude all other plants and displace native vegetation such as willows. They can supplant other plants as nectar sources and thus reduce their pollination. Their name notwithstanding, the bushes likely affect negatively native butterfly populations. Once established, these shrubs are difficult to remove because they re-sprout very easily.
What should I do if I find one?
How can we stop it?
Replace a butterfly bush growing in a garden with native plants, or at the least, deadhead it to prevent seeds from spreading. The butterfly bush is listed as a Class B Noxious Weeds in Washington, meaning it is designated for control in certain state regions.
What are its characteristics?
- It is a deciduous shrub with arching branches that can reach a height of 15 feet.
- The leaves and stems are typically hairy and are often green or blue-gray above and whitish on the underside, due to the fuzzy hairs.
- Leaf stalks are short and hairy, although the leaves sometimes are attached directly to the stem.
- They have small, fragrant flowers that are white to deep purple, with an orange-yellow inside.
- Flowers cluster together in groups that may be 4-10 inches long.