How to Care for Bufferfly Bush (and Remove Invasive Ones Correctly)

Butterfly collecting pollen from a purple Buddleja

Butterfly bush (Buddleia or Buddleja) is native to Asia and is often recommended to gardeners as a nectar plant for butterflies, bees, and other pollinators. However, some varieties of this flowering shrub are quite invasive and illegal to grow in some states. If you want to grow butterfly bush, there are a few important things to keep in mind.

Butterfly Bush Pros and Cons

Butterfly bushes have a bit of a reputation among gardeners. Some love them for their color and the fact that they attract pollinators. Others have had to struggle with trying to eradicate an invasive butterfly bush and completely revile them.

Pros of Growing Butterfly Bush

There are several reasons to grow buddleia, which is why (despite its reputation for being invasive) it continues to be a popular plant.

  • Pretty, long-lasting blooms
  • Attractive to wildlife, including monarch and swallowtail butterflies, hummingbirds, and bees
  • Resistant to deer and rabbit damage
  • Unique cut flower that lasts a long time in a vase

Cons of Growing Butterfly Bush

Of course, buddleia also has a few cons that are worth considering before you add this plant to your garden.

  • The most common variety, Buddleia davidii 'Black Knight,' can be invasive and is even illegal to grow in some states.
  • Some cultivars take up a large amount of space in the garden (needing about five or more feet of space for its maximum size).

Butterfly Bush Care

Butterfly bushes are fairly low maintenance. If provided with the right location (and especially if you make sure not to plant the invasive wild variety) a butterfly bush will grow and bloom for years to come.

Most butterfly bushes are hardy to zone five or six; if you live in a colder climate, you can still grow them, but you should be sure to mulch them deeply with fall leaves or evergreen branches in late fall or early winter to prevent the roots of the plant from being damaged by the cold.

In this climate, they'll die back to the ground every year, but new branches will sprout from the roots. Be patient; buddleia is a notoriously slow starter in the spring, and it's easy to assume the plant didn't make it through the winter. Once it gets going, however, it will grow quickly.

Light and Soil Preferences

Butterfly bushes prefer a site with full sun to partial shade and well-drained soil. They are prone to root rot, so if you have heavy clay soil, or a spot that stays wet, butterfly bush likely isn't a great choice for that particular spot. Of course, you can amend clay soil to make it more hospitable to plants.

Beautiful summer flowering Buddleja

Watering and Fertilizing

During dry spells (and especially during the plant's first year, when it's getting established in your garden) be sure to water deeply. In general, after the first year, butterfly bushes need about an inch of water per week.

Buddleia really don't need to be fertilized unless they're planted in very poor, low-nutrient soil. A topdressing of compost around the plant each spring is really all it needs to be happy.

Pruning

If you live in a cold area (zone five and six especially) butterfly bushes will likely die back each year and sprout new branches from the base of the plant the following spring. In this case, any pruning you have to do will be to remove dead or damaged branches, or to cut off spent blooms.

However, if you live in a warmer zone, it won't die back, and it will continue growing, blooming on the current year's growth. Buddleia grown in warm climates can get quite large; up to a 15 foot spread.

To keep it under control and keep it from shading out any other plants in the bed, you might have to prune it back. This is best done in late winter before new growth starts.

Of course, you can also just hack the entire plant down in fall, and it will sprout from the roots just as any perennial would.

If you are growing wild buddleia, or an invasive variety like 'Black Knight,' you'll want to be absolutely sure to deadhead, removing spent flowers before they can go to seed. This will help prevent the plant from spreading.

Pests and Other Issues

Yellowing leaves are a common symptom of root rot setting in. Cut back on watering, and consider either digging the plant up and amending the soil (if the soil is very heavy) or moving the plant to a different spot in your garden.

Japanese beetles sometimes feed on the leaves of butterfly bushes. If you notice that the leaves have holes or look otherwise nibbled on, inspect the plant and pick off any beetles.

Non-Invasive Butterfly Bush Varieties

While the native butterfly bush, Buddleia davidii, is invasive especially in warmer climates, plant breeders have developed several varieties that have the attractive blooms and pollinator-attracting qualities of the native version, without the danger of having the plant take over your garden.

  • 'Miss Pearl' blooms in pure white and grows to about five feet tall by five feet wide, hardy in zones five through nine.
  • 'Lo and Behold' is a line of butterfly bushes, available in a variety of colors from blue, to purple, pink, and white. These are a smaller variety, growing to about two feet tall and wide, so they're perfect for smaller gardens or for growing in containers.
  • 'Asian Moon' has dark purple flowers (which makes it a good alternative to 'Black Knight,' which is very invasive) and grows up to seven feet tall and five feet wide. It's hardy in zones six through ten.
  • 'Miss Molly' produces vibrant pink flowers on plants that grow up to five feet in width and height. It's hardy in zones five through nine.
  • 'Flutterby' is another line of non-invasive butterfly bushes that grow to about two and a half to three feet tall and wide, so this is another good option for small gardens. There are a variety of colors in this line, including blue, purple, pink, and white. 'Flutterby' buddleias are hardy in zones five through eleven.
    Peacock butterflys on buddleia flower in sunshine

What to Plant With Butterfly Bush

Butterfly bushes do offer nectar to bees, hummingbirds, and adult butterflies, but that's about all they offer in terms of wildlife habitat. If you're trying to provide a haven for butterflies, you'll also need to include plants that serve as host plants for the adults to lay eggs on, as well as plants to provide food for the caterpillars.

Trees and Shrubs

There are several trees and shrubs that serve as host plants or food sources for caterpillars.

Annuals and Perennials

Of course, annuals and perennials are an essential part of any wildlife habitat or pollinator garden. The ones listed below are pollinator magnets.

  • Aster
  • Black-Eyed Susan
  • Columbine
  • Dill
  • Echinacea (coneflowers)
  • Fennel
  • Goldenrod
  • Milkweed
  • Parsley
  • Verbena
  • Zinnia

How to Get Rid of an Invasive Butterfly Bush

If you have an invasive butterfly bush and you want to get rid of it, the only way to do so is to dig the plant up, getting as many of the roots as possible.

You'll also have to be careful about how you dispose of it. If you compost this overly-enthusiastic plant, chances are good that it'll just start growing in your compost pile. Burying it won't work; it'll most likely work its way up to the surface again.

  • Burning: This is a good option, and will ensure that the plant can't spread anywhere. Just keep local ordinances and safety in mind.
  • Smothering: Once you dig the plant out, if you can't burn it, consider placing it in a double-bagged black trash bag. Set it aside for a few months. After several months of no light or water, the plant should be dead and then you can compost it.
  • Municipal collection: some cities and towns have methods for helping homeowners dispose of invasive plants. If butterfly bush is invasive or illegal to grow where you live, check with your municipality to find out how you should dispose of it.
Digging up a large bush

Choose Wisely and Enjoy

Butterfly bushes are an attractive addition to the landscape, but the wrong variety can do more harm than good. Choose a non-invasive, sterile variety, and, if you're removing an invasive one, do so carefully to ensure it doesn't spread further.

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