Butterfly bush (Buddleja davidii) flowers close up
Photo by Forest and Kim Starr

butterfly bush

Ratings

  • This plant has a Plant Risk Evaluator rating of High Potential Risk
  • This plant has been rated Watch by the California Invasive Plant Council

Description

Native to East Asia. It was brought to the U.S. in the early 1900's as an ornamental shrub.

Grows to 5-15 ft. high and wide. Leaves are gray-green above and white and fuzzy underneath. Flowers are in long, erect, nodding spikes 8-18 inches long. The seeds it produces are abundant, dust-like, and dispersed by wind. It readily invades disturbed sites and riparian areas. Butterflies can use the plant as a nectar source but cannot use it as a host plant for their larvae. Las Pilitas Nursery has information about which plants provide food for adult butterflies and their larva in California. Other links below can provide you with ecoregional planting guides to help pollinators where you are.

In California, Buddleja davidii has naturalized in coastal areas in the north, the Bay Area, and a few locations on the south coast. See the Calflora map for its current distribution outside of cultivation.

Removing spent flower clusters can prevent self-seeding, but it produces so many blooms that deadheading would be a lot of work. If you cut the plant back, do not leave the clippings on the ground, as they can easily take root and create a new plant. Do not dump any clippings along a roadside or waterway.

The Oregon Department of Agriculture in cooperation with Oregon State University developed a criteria and process to approve sterile cultivars of butterfly bush. Cultivars that produce less than 2% viable seeds are placed on an approved list.

Approved cultivars include:

These cultivars have been proven to be interspecific hybrids through testing and laboratory analysis. Their fertility has not been assessed, but interspecific hybrids generally exhibit low fertility.

Why is this plant not included on the invasive plant list?

Buddleja davidii was considered in 2015 but not added as a candidate plant to the survey because more research is needed about the invasive risk of the various cultivars of Buddleja davidii, and because it has only naturalized in some locations on the coast of California. The risk based on what we know is not high enough to consider adding it to PlantRight's list.