Butterfly bush
(Buddleia or Buddleja davidii) |
WDFW is playing catch-up to that listing by removing butterfly bush from program packet materials. But thousands of copies of BWS plant lists have been distributed over the last 24 years, so help us spread the word: No more butterfly bushes please – at least not B. davidii (other species, like B. globosa and B. marrubifolia, are not invasive.)
Butterfly bush, sometimes called summer lilac or orange eye,is a native of China that provides lots of nectar throughout the summer and fall to many feeding adult butterflies. It requires almost no water, insecticides, or fertilizer to keep it healthy and productive. Its beauty and benefits to butterflies, plus its tough, virtually indestructible nature, have made it a gardener’s favorite.
But the some of the same qualities that make it popular also make it a serious problem. In its native range, butterfly bush is adapted to colonizing new areas, such as river banks disturbed by floods, and rapidly forming mature, seeding stands that can resist invasion by other fast-growing plants. Its ability to grow in low-nutrient, low-moisture soil makes it perfectly suited for colonizing sandy river banks.
Its resistance to garden insects also makes it poor habitat for the caterpillars and other critters needed to sustain the wildlife food chain. This is especially true on our rivers and streams where insects feeding on native shrubs and trees fall into the water to feed salmon and other fish.
Butterfly bushes crowd out the willows that are such good habitat for many of our native butterflies. Unlike butterfly bush, willows provide food for both the larvae and the mature butterflies.
Once established, butterfly bush is difficult to remove. It will re-sprout from the rootstock after its stems are cut, and the cut stems can also grow into new plants. If you don’t find new seedlings near your established plant, it doesn’t mean it’s not spreading. Butterfly bush seeds are small and dispersed by wind for many miles from the parent plant. They seem to germinate best in well-drained, open areas, not necessarily in rich garden soil where they compete with lots of other plants. The seeds, which can be produced during the first year of a plant’s life, can remain viable for up to five years.
Escaped, invasive populations of butterfly bush are especially pervasive in western Washington, including Clallam, Whatcom, Skagit, Snohomish, King, Thurston, Lewis, Cowlitz, and Clark counties. (B. davidii does not spread as much in the arid east side of Washington, compared to the mesic, or moderately moist, westside.)
You can stop your butterfly bush from spreading out of your garden by picking the flowering spikes before they produce fruits and cutting off the flower stalks in the fall. The seeds usually disperse over the winter and in the spring, so cut the flowers in the fall, don’t wait until your spring garden clean up.
If you’re up for complete removal of your butterfly bush, you can dig up the entire plant and dispose of it. Or you can cut and dispose of branches, then apply an appropriate herbicide to the stump to avoid basal roots sprouting. In its place, plant another flowering shrub –something from the BWS list that’s both wildlife and whole ecosystem friendly -- to avoid a rogue butterfly weed seed from taking off again.
In Oregon, it is now against the law to sell butterfly bush. The Washington State Department of Agriculture has not put butterfly bush on the prohibited plants list that regulates what nurseries can sell. As a Class B noxious weed, Washington requires control of the plant and encourages removal where possible.
For more information see the Washington Noxious Weed Control Board website at http://www.nwcb.wa.gov/index.htm . |
