Age-Old Wisdom meets Modern Tools
How to Plant, Grow, and Care for Butterfly Bushes
The butterfly bush (Buddleia davidii) is a beautiful, fast-growing, deciduous shrub with masses of blossoms—long, spiked trusses—that bloom from summer to autumn.
Its flowers come in many colors, though butterflies seem to prefer the lavender-pink (mauve) of the species to the white and dark purple cultivars.
Also called “summer lilacs,” butterfly bushes are hardy to Zone 5 and remain evergreen from Zone 8 south. The shrub is low-maintenance, only requiring dead-heading and annual pruning in later winter to encourage flowers and a compact shape.
Please note that the butterfly bush, originally imported from China, has been classified as an invasive species in most U.S. regions. In other words, the butterfly bush is known to crowd out native plants that are essential to wildlife, including butterflies and birds. In warm climates, it can become a noxious weed and spread aggressively, while in cooler climates, it mostly stays contained within a garden’s cultivated soil if gardeners deadhead the flowers.
Despite the “butterfly” name, keep in mind that this shrub is not a “host plant” for butterflies in that it does not support butterfly reproduction and lifecycle. Caterpillars do not feed on butterfly bushes; rather, it only provides nectar to adult butterflies. If you do have a butterfly bush, be sure to add native host plants such as milkweed, aster, and dill if you want the butterflies to stay. See plants that attract butterflies.
If you would still like to put a butterfly bush in your garden, there are a few species of non-invasive butterfly bushes native to the southwestern US. Please check with your local cooperative extension for more information.
Planting Butterfly Bushes
- Buddleias need full sun and fertile, well-drained soil.
- Plant in spring or fall before frost. See your local frost dates.
- Loosen the soil, mix in compost, and dig a hole twice the diameter of the plant container.
- When placing the plant in the hole, the top of the rootball should be level with the soil surface
- Space plants 5 to 10 feet apart, depending on the variety.
- Water thoroughly.
Caring for Butterfly Bushes
- Water freely when in growth and sparingly otherwise. In the summer, water if rainfall is less than 1 inch per week.
- Avoid fertilizing butterfly bush; too much fertility promotes leaf growth over flower production.
- Remove spent flower spikes to encourage new shoots and flower buds.
- In addition, it is important to deadhead the flowers just as they start to wither so that this invasive plant doesn’t spread volunteer seeds. Deadheading of this invasive is now required in many states.
- Each spring, apply a thin layer of compost and mulch to retain moisture and control weeds.
- In cold, Northern climates, spread mulch up to 6 inches deep around the trunk to nurture it through the winter.
- Buddleias are very late to break dormancy, so don’t be in a hurry to assess winter damage.
- The bush should bloom abundantly even in its first year. In warmer climates, the bushes will grow into trees and develop rugged trunks that peel; peeling is normal.
- In the northern limit of their range, they behave as herbaceous perennials, dying back to the root in cold winters.
- Since they bloom on new wood, even if there is no die-back, cut them back to the ground every spring. Yes, hack to the ground!
- Even where winters are mild enough for the stems to survive, prune severely to stimulate abundant growth on which flowers are borne.
We are no longer recommending new plantings of the butterfly bush, given its categorization as an invasive in most of North America. Instead, we recommend using plants that better support the native landscape and food web, given our declining pollinator population. See alternative plants that attract butterflies.
Here are a few great flowering alternatives that also serve as host plants for caterpillars:
- Asters (Symphyotrichum)
- Beardtongue (Penstemon)
- Bee Balm (Monarda)
- Black-Eyed Susan (Rudbeckia)
- Columbine (Aquilegia)
- Coneflowers (Echinacea)
- Goldenrod (Solidago)
- Irises (Iris)
- Milkweed (Asclepias)
- Rhododendrons & Azaleas (Rhododendron)
- Spicebush (Lindera)
- Strawberries (Fragaria)
- Verbena (Verbena)
- Viburnum (Viburnum)
- Yarrow (Achillea)
See a list of host plants native to your area here: Native Plant Finder