Butterfly bush (Buddleia davidii) is a deciduous shrub with an arching habit and impressive flowers. It's easy to grow and produces striking flower spikes. Thanks to the magic of cultivar developers, the flowers now come in a number of colors, including pink, yellow blue, and multicolors. As the name suggests, these shrubs are known as magnets for butterflies and other pollinators. Red-flowering butterfly bushes will even attract hummingbirds.
Butterfly bushes are cultivated to suit many different gardening preferences. Some can grow up to 12 feet tall, while others are relatively small. Some varieties produce large clusters of flowers while others produce flowering spikes. Butterfly bushes were first brought to England from Asia in 1774 by the botanist Adam Buddle (for whom the plant was named). New varieties are still being discovered in remote areas of China and the Himalayas.
While the plant is enjoyed by many, butterfly bush does have detractors. In certainareas of the United States, it's actually considered an invasive plant—one that does not naturally grow in a particular region but which is pervasive enough to push out native plants. As a result, many plant experts caution against planting butterfly bush under any circumstance.
Invasive plants are problematic because they can alter ecosystems and damage existing flora and fauna. Although not invasive everywhere, butterfly bush is meddlesome enough to have given the plant a bad name. Several states now classify it as a noxious weed. There are good reasons not to plant the butterfly bush, especially in regions where it is an identified problem. If you are unsure about this plant's status in your area, check with your local agricultural extension office before adding it to your landscape.
|Botanical Name||Buddleja davidii|
|Common Names||Butterfly bush|
|Plant Type||Deciduous shrub|
|Mature Size||4 to 12 feet tall; 3- to 8-foot spread (depends on variety)|
|Sun Exposure||Full sun|
|Soil Type||Medium moisture, well-drained soil|
|Soil pH||6.0 to 7.0; slightly acidic to neutral|
|Bloom Time||June to September|
|Flower Color||Shades of purple; also pink, blue, white, yellow|
|Hardiness Zones||5 to 9 (USDA)|
|Native Area||Rocky slopes in China|
How to Grow Butterfly Bush
The popularity of butterfly bushes is no surprise as they're beautiful, easy to grow, and require minimal day-to-day care. Even major storms have little effect on these hardy shrubs. They thrive in harsh environments, such as polluted urban settings. They're also resistant to insect pests, drought, and stress. The bushes require little attention, so even weekend gardeners can enjoy their lovely blooms and resident butterflies.
Butterfly bush grow well in average, medium moisture, well-drained soil in a full sun location. If planting more then one, space them well apart—five to six feet. Blend in peat moss before planting if the soil is dense and poorly draining.
In colder climates, butterfly bush often dies back to the ground in winter and is treated like a herbaceous perennial. In warm climates, they can be pruned back in the same way to keep them under control and stimulate better blooming. Be wary of this plant's tendency to aggressively spread through self-seeding. Removing the spent flower clusters before they can scatter seeds will help control the plant.
There are no serious pest or disease problems with butterfly bush, although spider mites can be an issue and nematodes can be a problem in the South.
Butterfly bush needs full sun and will become weedy and sparse if grown in shady conditions.
This plant will thrive in any average, well-drained soil that gets an average amount of moisture.
This plant likes a medium-moisture environment and will do poorly in boggy locations that don't drain well. They will thrive on 1/2 inch of water by rain or irrigation each week.
Temperature and Humidity
Butterfly bush thrives throughout its hardiness zone range, but expect it to die back to ground level in winter in zones 5 and 6.
This plant needs no fertilizer, other than a thin layer of compost spread over the root zone each spring.
Propagating Butterfly Bush
It's rare that you would seek to propagate this bush, since it spreads so readily, but if you do, collecting the seeds heads will give you plenty of seeds to replant wherever you wish.
Propagation by seed is not possible if you have wisely chosen a sterile, seedless variety of butterfly bush. With these, propagating by spring branch cuttings is the best approach.
Varieties of Butterfly Bush
Butterfly bush should be planted with caution, and only if you are willing to remove spent flower heads to avoid spreading the seeds. While there are many popular varieties, including Buddleia x weyeriana 'Bicolor', and Buddleja davidii 'Black Night', better choices are offered by newer non-seeding varieties:
- Buddleja x 'Blue Chip' is a smaller, 3- to 6-foot variety that is sterile and produces no seeds. Its flowers are purple.
- Buddleja 'Miss Ruby' is another sterile variety, growing 4 to 5 feet tall and wide, with pinkish-purple flowers.
Other cultivars that are bred to be seedless include 'Asian Moon', 'Ice Chip', 'Inspired Pink', 'Purple Haze', and the various Flutterby Grande cultivars.
The spent flower spikes of butterfly bush should be removed promptly after flowering to stimulate continued blooming right up to frost. This plant grows rapidly, and pruning it all the way to ground level each spring stimulates vigorous growth and profuse flowering.