How to Grow Butterfly Bush (Buddleja davidii)

By Matt Gibson

The butterfly bush is a lovely deciduous shrub with hefty masses of flowers in the form of long, pointed trusses ranging from white to pink, lavender and deep purple. The fast-growing, low-maintenance shrub is hardy to USDA zones five through nine and is a great addition to your garden, especially if you are wanting to entice butterflies to come to your garden and assist with pollinating your plants.

If you have a butterfly bush in place to bring butterflies in, pair it with milkweed, aster, and dill to keep those butterflies around for a while. Butterfly bush gets its name for having the ability to attract the pollinators to the garden. It is not a host plant for butterflies, and it will not support nymphalid reproduction, brace butterfly life cycle, or fatten up growing caterpillars. It just produces nectar that adult butterflies enjoy.

A native of China, the butterfly bush, though quite beautiful and ornamental, has been labeled an invasive plant in the United States. Plants receive the invasive classification because they are known to aggressively crowd native plant species which are essential to local wildlife, including beneficial insects, like butterflies, and pollinators, like the birds and bees.

In cool climate areas, its spread is much less aggressive, and it typically stays within the borders of a garden bed as long as its spent blooms are regularly cut back. If flowers aren’t deadheaded in cool climate zones, butterfly bush will spread, but too slowly to be considered an invasive. In warm climate areas, butterfly bush turns into a noxious weed and spreads like a pandemic.

It’s not just the nectar that butterfly bush produces that brings in the pollinators, but also the aroma. Considered just as fragrant as it is aesthetically pleasing, Long flower clusters of vibrantly-colored, nectar-filled flowers pop up along the shrub throughout the summer months, attracting lots of butterflies and other pollinators to your home garden. Its resilience is another added perk, as it is quite drought tolerant and mostly disease resistant.

Varieties of Butterfly Bush

Due to its invasive nature, butterfly bush should be grown with some caution. If you want to keep butterfly bush varieties in your garden, you will need to deadhead blooms regularly to avoid self-seeding. If you are a fan of the butterfly bush, however, and are ready to deadhead when needed, here are a few of the best varieties to cultivate, including a group of seedless varieties:

Black Night – A popular, extra-hardy variety with dark purple blooms.

Blue Chip – A small, three to six foot plant with purple flowers and no seeds.

Flutterby Grande (cultivars) – A group of seedless varieties in various colors.

Honeycomb – A medium-sized plant with yellow blossoms.

Ice Chip – A dwarf cultivar with pale white blooms.

Inspired Pink – A lovely pink variety bred to be seedless.

Lilac Chip – A dwarf cultivar with light purple blooms.

Miss Ruby – A four to five-foot sterile cultivar with pink-purple flowers.

Purple Haze – A purple cultivar with hints of pink and no seeds.

White Profusion – Regular size shrub with short, white blooms.

Though these cultivars are wonderful selections if you are looking for butterfly bushes specifically, if you want plants that attract butterflies and also can be used to serve as host plants for caterpillars, try your hand at growing any of the following flowering plants:

Asters, Azaleas,Black-Eyed Susans, Columbines, Coneflowers, Irises, Rhododendrons, Strawberries, Verbena, and Yarrow.

Growing Conditions for Butterfly Bush

Butterfly bush requires full sun, as it will turn weedy, leggy, and sparse, if provided with shady locations. Plant butterfly bush into any soil medium, as long as it is provided with a medium amount of water, and a well-draining soil. Butterfly bush will suffer in boggy or soggy locations with poor drainage. Provide about one half-inch of water either by rain or irrigation every week. Butterfly bush thrives in zones five through nine but will regularly die back down to the ground in the wintertime in zones five and six.

How to Plant Butterfly Bush Transplants

In the spring or in autumn just before frost, loosen the soil and amend with compost. Dig a hole for the plant that is twice the diameter of the plant container. Place the rootball into the hole so it is level with the soil’s surface. Space plants out at least five to ten feet apart, depending on the size of the variety. Water the plants thoroughly right after transplanting to help ease the plant’s transition into its new home.

Care for Butterfly Bush

Water regularly during the growing season and cut back on watering when there is no new growth. In the summertime, provide water only if rains give under an inch each week. Don’t fertilize your butterfly bush, as too much nutrients encourages leaf growth and lessens flower production.

Deadhead faded flower spikes to promote new shoots and new bloomage. Remove spent flowers right as they begin to wither so that it doesn’t drop unwanted volunteer seeds. Butterfly bush is so invasive when flowerheads are not cut back regularly, that deadheading the plant is actually required in a number of states.

Every spring, lay out a thin layer of compost and mulch to improve moisture retention and deter pesky weeds. In cold climates, lay out mulch thickly, up to six inches around the trunk of the shrub to help protect it from harsh winter temperatures.

Butterfly bush is abnormally late to come out of dormancy, so don’t worry about winter damage unless there is no new growth by mid-spring. Butterfly bushes should have plenty of flowers from the first year and beyond.

In warmer climates, shrubs will likely turn into trees with peeling trunks. In the far north, expect the bushes to die back to the root in cold winters and sprout back up in the springtime. Trim back down to the soil each spring even with no noticeable die-back, as butterfly bushes are known to bloom on new wood growth. Even in mild winter climates, prune aggressively to increase vigorous growth on woody stems.

How to Propagate Butterfly Bush

Butterfly bush is rarely ever propagated, due to how rapidly it spreads and how most commonly cultivated varieties are sterile or seedless to stop invasive spreading. However, propagating from seed is still possible. Just collect the seed heads and you will have all the butterfly bush seeds you could ever need for planting. Seedless, sterile varieties can be propagated by branch cuttings dipped in root hormones and rooted in a moist substrate.

Garden Pests and Diseases of Butterfly Bush

Butterfly bushes don’t get a lot of pest attention, however, spider mites, mullein moths, and caterpillars can attack the plants on occasion, and butterfly bush is sometimes troubled by fungal infections. Knock insects off the plants with a burst of water from the garden hose or mist the bushes with an insecticidal soap spray. Avoid chemical treatments, as they can also harm the butterflies, bees, and other pollinators attracted to the colorful bushes.

For fungus issues, try to keep foliage as dry as possible or water plants early in the morning so that they are dry by the time the weather gets hot or muggy. Prune back diseased plant parts and burn or discard them to keep fungal spores from spreading. Give your plants a generous layer of mulch to help them survive the winter temperatures. Either prune bushes all the way to the soil near wintertime and give plants compost and more mulch when they break out of dormancy in the spring, or prune right before new spring growth occurs.

Butterfly bush is a beautiful shrub to add to a flower garden or to add to the back row of tall perennial flower borders. Plant dwarf varieties in the front of flower bed borders or pop them in containers to enjoy on the patio, where their invasive properties will have no effect. No matter where you choose to plant the butterfly bush, remember to deadhead regularly to discourage rampant spreading, and remember to enjoy the hordes of pollinators that your butterfly bush or bushes will bring to the garden as it blooms.