Q. Can you provide some information on growing butterfly bush?
Butterfly bush (Buddleja davidii and its many cultivars and hybrids) blooms from early to mid-summer all the way into fall, its fragrant flowers attracting butterflies, bees and hummingbirds. These tall, arching plants are easy to grow; once established, they tolerate drought, heat and humidity.
However, this Asian native comes with a couple of serious drawbacks. A prolific seed producer, Buddleja can be invasive, outcompeting and pushing out native plants that are integral to local food webs. Oregon and Washington have banned the sale of Buddleja davidii; many other states have it on their watch lists. Additionally, although its nectar attracts a variety of North American butterflies, such as black swallowtail, eastern tiger swallowtail, great spangled fritillary, monarch, painted lady, and western checkerspot, this plant is not a host plant for any native caterpillars. In order to reproduce, butterflies must find native plant hosts. Rodale's Organic Life details these drawbacks in 3 Reasons Never to Plant Butterfly Bush Again.
Native caterpillar hosts include butterfly weed, other milkweeds, joe-pye weed, and oak trees. If you grow butterfly bush, you may want to provide some of these native hosts as well.
To counteract the invasiveness problem, many seedless or low-fertility Buddleja varieties have been developed in recent years.
You can add butterfly bush to your garden in spring or fall. Loosen the soil 12-15 inches deep and mix in a 2- to 4-inch layer of compost. Dig a hole twice the diameter of the pot the plant is in. Remove the plant from its container and place it in the hole with the top of the rootball level with the soil surface. Water thoroughly. Each spring, apply a thin layer of compost followed by a 2- to 4-inch layer of mulch to retain moisture and control weeds. Water plants during the summer if rainfall is less than 1 inch per week. Avoid wet locations, which can cause root rot. Flowers are produced on new wood, so prune back old growth almost to the ground early each spring before any new growth emerges. Cutting back eliminates twiggy shapes, keeps plant size somewhat smaller, and produces larger flowers.
Butterfly bush are deer-resistant and tolerate urban pollution. Because the buds grow on new wood, winter damage to stems won't affect flower development. Deadheading reduces seeding and encourages reblooming.
Blooms on the long, cone-shaped panicles can be blue, pink, red, violet, yellow or white, depending on the variety. There are many to choose from. Here are a few top performers:
- B. davidii ‘Attraction’: 12-inch-long red-purple inflorescence; neat, compact habit
- B. davidii ‘Red Plume’: closest to a real red; colossal flowers on tall plant
- B. davidii ‘Purple Haze’: compact, sterile cultivar; countless purple blooms arching over low-spreading plant
- B. davidii ‘White Bouquet’: large, robust bush, white flowers with yellow throats, silver-green leaves
- B. davidii ‘African Queen’: thickly dark violet florets clustered on 12-inch plumes
- B. davidii ‘Adonis Blue’: blue-purple flowers, gray-green leaves, well-branched, compact habit
For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service