Butterfly Bush(Buddleja [or Buddleia] davidii) is a surefire attention-grabber. A common sight in our region’s gardens and landscape plantings, its fragrant conical blooms—typically festooned with fluttering butterflies and buzzing bees—are hard to miss.
Although eye-catching, hardy, and seemingly helpful to butterflies and other pollinators, Butterfly Bush is far from beneficial; in fact it’s actually an invasive species that can impair the health of our local ecosystems.
Origins
Although Butterfly Bush grows easily in our region, it is not native to North America. TheBuddlejagenus originated in central China and migrated across Asia and to the Americas, evolving into over 140 species as it spread.B. davidii,the most commonly cultivated species in our region, is a native of China.
Butterfly Bush is a deciduous shrub that can grow up to 15 feet high. The opposite-growing leaves, 5-10 inches long, have jagged edges. Butterfly Bush blooms from mid-summer to early fall. Flowers form drooping or upright spikes at the end of branches. The wild-origin species is white-flowered with orange or yellow centers. Varieties bred for the garden are typically purple; or they may have pink, blue, magenta, yellow or maroon blooms.
Reproduction
Butterfly Bush is extremely successful at reproduction, giving it a competitive advantage over native flowering shrubs. It excels at seed production and dispersal. A study at Longwood Gardens found that there were over 40,000 seeds on a single flower spike. The shrub reaches maturity quite quickly, often producing extremely lightweight, winged seeds within the first year of growth, which travel far distances by way of water or wind. The germination rate is about 80 percent or above. These seeds can remain viable for three to five years in soil, and any cut stems can sprout again.
Negative Impacts
Butterfly Bush benefits pollinators but only at one stage of their life cycle. It attracts butterflies because it provides copious nectar. However, butterflies need host plants on which to lay eggs and on which their caterpillars feed. Not a single native caterpillar eats Butterfly Bush leaves.
If Butterfly Bush were just a pretty garden shrub, it would be less of a concern. But its high reproductive success and dispersal means that Butterfly Bush replaces native shrubs outside the garden, in natural areas. It establishes in sunny, well-drained sites including fields, roadsides, woods edges, and riverbanks, where native shrubs would have grown. Those vanished native shrubs were essential food sources for caterpillars. Without caterpillars, there will be no adult butterflies. Without caterpillars, birds will not survive.
Instead of planting Butterfly Bush, select a native flowering shrub appropriate for your site that is attractive to pollinators. For sunny, open garden or landscape plantings, try Sweet Pepperbush, also called Summersweet(Clethra alnifolia)or Virginia Sweetspire(Itea virginica). For wetter soils, try Buttonbush (Cephalanthis occidentalis)—a food source for moths—or New Jersey Tea (Ceanothus americanus). You can also plant drifts of tall native perennials. Favorites of butterflies include Blazing Star (Liatris); Purple Coneflower (Echinacea purpurea); Giant Hyssop (Agastache); Joe-Pye Weed (Eutrochium) species and Milkweed (Asclepias) species.Click here to find more ideas for butterfly plantings.
Control
Butterfly Bush can be difficult to manage once it has been established. Seedlings can be manually removed. It is possible to uproot and dig out mature specimens. The roots must be removed or they will re-sprout. Areas around the removal site should be planted with a native ground cover to prevent future seedling germination. You must dispose of any plant material completely, by burning or putting out in the garbage. Branches left on the ground can root into new shrubs.
If you already have Butterfly Bush as a planting, and do not want to remove it, you should prevent the spread out of your garden by removing old flowerheads in the fall prior to seed dispersal. Dispose of the flowerheads in a controlled manner. Do not dump clippings or flowerheads in natural areas or compost piles.
Goats can be helpful as a control method since they consume Butterfly Bush. Although grazing alone cannot entirely eradicate the weed, in tandem with another method—such as manual removal—they can be a successful control.
Non-invasive variants
There have been recent introductions to the garden markets of purportedly non-invasive Butterfly Bush. These plants have been bred to not set as much seed. If you simplymusthave a Butterfly Bush, these varieties may be an option, but keep in mind that they don’t provide butterflies with the hosting benefits of native flowering shrubs. And history is replete with plants touted as non-invasive that turned out to be just the opposite (case in point: multiflora rose). Eco-conscious gardeners would do better to opt for the native shrubs.
Header image: Butterfly Bush (Buddleja davidii) in flower (surrounded by native wildlfowers). Photo by Leslie J. Mehrhoff, University of Connecticut, Bugwood.org
Although eye-catching, hardy, and seemingly helpful to butterflies and other pollinators, Butterfly Bush is far from beneficial; in fact it's actually an invasive species that can impair the health of our local ecosystems.
Butterfly bush is an invasive plant, meaning it crowds out beneficial plants that have naturally grown in your community for centuries. This species originally from Asia readily takes over space where native North American plants would normally thrive.
Butterfly bushes grow and spread aggressively, often out-competing native plants. This can disrupt local ecosystems and decrease food and habitat availability for beneficial insects and other wildlife.
Washington isn't the only place where butterfly bush is a problem. England and New Zealand, as well as several states on the Eastern seaboard, recognize B. davidii as an environmental threat. Oregon put it on its noxious weed list earlier this year.
Chemical control: Controlling butterfly bush by spraying with a brush-control herbicide is somewhat effective, but for better results, cut the trunk off at the base and apply concentrated glyphosate (such as in Roundup) or triclopyr (such as in Garlon or Brush B Gon) to the freshly cut surface.
For sunny, open garden or landscape plantings, try Sweet Pepperbush, also called Summersweet (Clethra alnifolia) or Virginia Sweetspire (Itea virginica). For wetter soils, try Buttonbush (Cephalanthis occidentalis)—a food source for moths—or New Jersey Tea (Ceanothus americanus).
Butterfly bushes should be cut back to a foot tall to promote new growth and the best blooms. You can cut the shrub back to ground level; however, you take the risk of late frost or freeze killing new growth and losing the plant. Hard pruning is done in late February or early March depending on your climate.
Because butterfly bushes offer copious amounts of nectar, they become extremely attractive to pollinators, distracting them from other native co-flowering species, and reducing the native's reproductive success which eventually also harms the native's populations.
Typically, a butterfly bush will live about 10 years. You may find some plants that live longer than that, but it's a rare case. Proper care of a butterfly bush will help it live longer and thrive in your garden.
In habit, butterfly bushes are informal with a loose, open growth habit that does not hold a tightly manicured shape. Flowers are produced on new growth, so size can be controlled by cutting back quite hard in early spring, just before leaf buds begin to grow.
Mulch the plants generously to protect them during the winter. Many gardeners prune their butterfly bushes all the way to the ground in late winter. This dormant-season pruning allows extra root and evergy reserves to quickly heal the wounds and supports vigorous spring growth.
Butterfly Bush (Buddleia) has become very popular due to the growing interest in butterfly gardens. These beautiful shrubs make attractive landscape plants, and are known to be magnets for butterflies, bees, hummingbirds, and beneficial insects.
When & Where to Plant Butterfly Bush. Light: Butterfly bushes grow and flower best in full sun. They will grow fine in part shade, especially in warmer climates, but their flowering may be reduced. Soil: Butterfly Bushes are not particular about the soil conditions, as long as it drains well.
Butterfly bush has the most ecological impact by displacing native plants when it escapes to natural areas. Once established in a natural area, butterfly bush can displace native plants. Native plants are important for pollinators because they provide them with a natural nectar source.
Buddleias are, in fact, butterfly MAGNETS, drawing a wide range of butterfly and other pollinator species to them with their plethora of sweet-smelling flowers. So much so, that many butterfly gardens are designed around Buddleia as the core element to support these beautiful creatures.
Introduction: My name is Merrill Bechtelar CPA, I am a clean, agreeable, glorious, magnificent, witty, enchanting, comfortable person who loves writing and wants to share my knowledge and understanding with you.
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