-
Photo Credit: Kingsbrae Garden, Flickr -
Photo Credit: Forest and Kim Starr, Starr Environmental, Bugwood.org -
Photo Credit: Forest and Kim Starr, Starr Environmental, Bugwood.org -
-
Photo Credit: John Ruter, University of Georgia, Bugwood.org
Also known as: orange-eye butterfly bush, summer lilac
You can’t blame gardeners for adoring butterfly bush. The shrub’s purple-and-orange flowers are as dazzling to the human eye as they are to pollinators. Unfortunately, this attractive plant does not always stay where we plant it. When it escapes into natural areas, it can become extremely invasive, choking out native plants and damaging ecosystems.
Description:
| Life Cycle: | Perennial (life cycle lasts more than one year) |
| Early Detection and Rapid Response species: | No |
| Height: | 10 – 15 feet tall (3 – 5 meters) |
| Leaf Description: | Its large leaves are arranged opposite along the stem and are lance-shaped. Each leaf is gray-green with wooly, white hairs underneath. |
| Fruit & Flower Description: | Produces small, fragrant flowers arranged in a cone-shaped flower spike. Flowers have 4 petals and are commonly bright purple, other varieties may be white, pink, or red, but all have orange centers. Each flower cluster can produce up to 40,000 seeds per year. Its seeds remain viable in the soil for 3 to 5 years. |
| Bloom Time: | July to September |
Habitat:
- Butterfly bush prefers sunny locations with well-drained soil, but it will readily grow in cement cracks or extremely disturbed soils
- It can take over bare or disturbed sites, including roadsides, riparian areasRiparian Areas Areas of land that occur along the edges of rivers, streams, lakes, and other bodies of water., pastures, urban areas, and wetlands.
Impact:
- Butterfly bush only benefits pollinators at one stage of their life cycle. It provides copious nectar for butterflies but it offers no food for native caterpillars. Its nectar is heavily concentrated and is essentially “junk food” for butterflies.
- It produces a lot of seeds. Its seeds are carried by wind, equipment, water, and in fill dirt to new locations.
- It forms dense thickets, especially along riverbanks and gravel bars, altering soil nutrients and crowding out native trees and shrubs.
What you can do about it:
- The biggest challenge for controlling butterfly bush is its popularity. In addition to naturally spreading, it is spreading because people are purchasing and planting it. There are many native alternatives available to plant instead of butterfly bush, Native Plants for Willamette Valley provides several options for local gardeners.
- If you have butterfly bush in your garden, make sure it doesn’t go to seed. Cut off fading flowers before they produce seeds, place them in a plastic bag, and throw them away in the trash — not your yard waste bin or home compost.
Look-alikes:
Butterfly bush looks similar to the Pacific Northwest native Douglas spirea (Spiraea douglasii). Douglas spirea has similar cone-shaped flower spikes but are usually pink rather than purple. Both plants blooms at a similar time, July through September.
Noxious Weed Listing:
| State of Oregon: | Class B |
| State of Washington: | Class B |
More Resources:
Download the Butterfly Bush Best Management Practices Factsheet
- Pacific Northwest Weed Management Handbook: Butterflybush
- University of California, Weed Research & Information Center: Butterflybush