The Butterfly bush (Buddleia davidii) is a resilient, hardy plant that originated in China. They are sometimes called “summer lilacs” because of their long, flowered trusses that resemble lilac flowers.
Butterfly bushes are easy to care for plants that come in many colors, like mauve, white, purple, and orange. Once established, they are drought resilient. They require little maintenance apart from annual pruning and deadheading. But butterfly bushes are considered invasive in many areas around the country. So it is important that you consult with your local extension office before planting to ensure it is permitted in your region. If it is, the butterfly bush can be a lovely, colorful addition to your outdoor space!
Read on to learn more about the butterfly bush, how to control its spread, and how to keep it healthy and safely contained in your area!
About the Butterfly Bush
Butterfly bushes were brought to Europe from Asia in the late 18th century. The most common variety, buddleia davidii, is just one of the hundreds of species in this genus. And new varieties of the butterfly bush are still being discovered in Asia to this day.
Butterfly bushes are deciduous, woody shrubs that produce beautifully colored flowers. Their flowers come in colors ranging from lavender to pink to white and dark purple. They bloom well, even in their first couple of seasons of growth. And their flowers are fragrant and bright.
Because of their fragrance and color, their flowers attract butterflies, as their name would suggest. They also attract other pollinators like bees and hummingbirds. Though the plant attracts butterflies, it is not a good host for their reproduction or for their complete lifecycle. If you want to sustain the lifecycle of butterflies, you may consider creating a butterfly garden. Butterfly gardens have plants that can support all life stages of the butterfly. Your butterfly bush is a perfect beginning to a butterfly garden!
The plants are fast-growing and can grow from 6-12 feet tall and 4-15 feet wide. However, they are not always that large. The size can vary with different cultivars. For example, there are dwarf varieties that remain only around 18 inches tall and wide.
Butterfly bushes are hardy from zone 5-9. In winter, butterfly bushes are evergreen, meaning they retain their leaves if the temperature does not drop below 20 degrees Fahrenheit. Though they may lose their leaves if it becomes colder than 20 degrees, they can still survive in colder temperatures. Although severe and sustained freezing temperatures may kill the roots. If you are concerned about your butterfly bush freezing, try adding extra mulch to the plant’s base before winter. If temperatures rise above 90 degrees Fahrenheit consistently, this may inhibit the plant from flowers.
Butterfly Bush: Planting & Growing
When planting your butterfly bush, be sure to plant in spring or fall before a frost. And consider planting your bush near a door or window, so you can enjoy the fragrance as they bloom. If you must plant in the fall, be sure to do so well before the first frost to allow the bush’s roots to develop.
When planting, dig a hole two times the size of the container that your bush came in. Mix compost into the soil around the hole. Remove the bush from its container and place it in the hole. The top of the rootball should be level with the soil surface. Water your newly planted bush thoroughly for the first couple of weeks to help the roots take hold.
If you are planting more than one plant, be sure to space them 5-10 feet apart, to allow room for future growth.
Butterfly bushes are fast-growing bushes. They can grow to their mature size in just one to two growing seasons. In warmer climates, they grow into trees with peeling bark. This peeling is common for butterfly bushes and should not be cause for concern.
They are very efficient at reproduction as well, which is why they are so invasive to native species. Just one flower cluster can produce thousands of seeds, which easily travel far distances through wind or water.
The seeds can remain viable for 3-5 years in soil, and their germination rate is above 80%.
Butterfly Bush General Care
Butterfly bushes grow best in full sun. They can tolerate lower light and some shade, but they may not flower as well.
Watering the Butterfly Bush
Watering your butterfly bush well is especially important right after planting. After your bush is established, be sure your bush receives water regularly, especially during the growing seasons. If they receive less than one inch in a week, water them manually. Once the bushes are established, they are drought tolerant. So do not worry if you cannot water your plant regularly for a short period of time.
Avoid overwatering, which you can identify by weak stems, fewer flowers, and dieback.
Butterfly plants prefer fertile, well-drained soil. Well-draining soil is beneficial because soil that is always wet will encourage root rot. Ideally, the soil should be between a pH of 6.0-7.5 (slightly acidic to neutral) for optimal flower color.
If you live in an area with clay soil, you may still be able to successfully grow a butterfly bush, but consider making some modifications in your plant care. For example, in clay soils, it is best to avoid mulch (as it retains too much moisture).
It is also recommended that you plant your bush “high” instead of planting your bush at ground level. To do this, dig a more shallow hole so that the base of the plant does not quite reach the ground. This process creates an incline that will promote water to flow away from the plant rather than accumulating around it.
Fertilizing Your Butterfly Bush
Be careful to avoid over-fertilizing your butterfly bush. Bushes that are planted in good soil with proper lighting rarely need fertilizer. And over-fertilization can promote too much leaf growth and over-flower production. If your plant is in poor soil and does need fertilization, use an all-purpose balanced fertilizer and cover the area with compost and mulch. Each spring, re-apply mulch to the base of the plant to control weeds and help maintain moisture. If you live in a cold climate, add more mulch (up to 6 inches) to keep the bush insulated throughout the winter.
Pruning a Butterfly Bush
The most maintenance that your plant will need is annual pruning and removal of deadheads on the plant. Generally, it is best to prune your bush in early spring. When you prune your bush, cut it back to the ground. Butterfly bushes only produce blooms on new wood, so cutting them back is necessary to promote new growth.
Your butterfly bush will need regular attention as its flowers wither to ensure proper deadheading, as well. The deadheading of the butterfly bush is required now in many states due to its invasiveness.
In the spring and summer months specifically, remove dead flower clusters from your butterfly bush quickly. The clusters, if not removed, will mature to develop seed pods. These seedpods will then release their seeds nearby. One butterfly bush can produce millions of seeds in one season. Careful attention to deadheading is necessary to prevent the unnecessary spreading of the plant. If your seeds do happen to spread and little seedlings develop, be sure to remove them promptly. Do this by removing the entire plant from the ground completely. If the roots are left intact, the plant will reemerge.
Transplanting or Removal
Butterfly bushes can be difficult to manage once they are established. As mentioned above, immature seedlings can be removed or prevented through deadheading. For more mature plants, transplanting or removal is possible, though more challenging. To avoid resprouting, be sure to remove the entire root system of the plant. And, to control the spreading of the plant, be sure to carefully dispose of all of the plant material. Branches left on the ground can develop roots and establish new bushes, so be sure not to put clipping or branches in compost piles or bins. You can dispose of plant materials by burning them or by putting it in the garbage.
Butterfly Bush Pests and Diseases
Butterfly bushes are not highly susceptible to pests and diseases. Below are some troubles that might occur for you:
- Capsid bug
- Mullein Moth
- Spider Mites
- Japanese beetles
- Root rot
- Fungal leaf spots
It is recommended that pests be treated with natural pesticides. This will avoid harming the birds, bees, and butterflies that often visit these plants.
Avoid root rot by taking care not to overwater your plant and ensure it has good drainage.
Fungal leaf spots may be due to pests. A solution like neem oil will help protect your bush. Pruning away the infected parts of the plant will keep the fungus from spreading.
Butterfly bushes are one of many deer-resistant plants.
The butterfly bush is not toxic to humans or animals, but they are also not considered edible. There should not be cause for concern if a pet accidentally ingests some of your butterfly bush. However, a good rule of thumb is to keep them safe from children and small animals.
Although most butterfly bushes are planted in the ground, they can also be planted in pots. Dwarf varieties of butterfly bushes are best suited to this sort of planting. If you’d like to plant your butterfly bush in a container, be sure to choose a pot that has good drainage. Use well-draining, general gardening soil.
If you plan to keep your plant outside, make sure to purchase a container that can withstand the weather in your area. In very cold climates, you may still want to protect your plant by keeping it warm in a shed or garage.
Butterfly bushes are sometimes confused with butterfly weeds. This weed is an herbaceous perennial that is a species of milkweed. Butterfly bushes, on the other hand, are deciduous, woody plants.
Not only that, butterfly weed is toxic to humans and animals, while butterfly bushes are not.
Benefits for Butterflies
Butterfly bushes have brightly colored flowers that attract butterflies. But their nectar is only helpful to butterflies themselves. It cannot provide nourishment to caterpillars (the babies of the butterfly life cycle).
If you want to support the full lifecycle of the butterfly, you may consider creating a butterfly garden. A butterfly garden is a garden of plants specifically designed to support the full lifecycle of the butterfly. To do this, you will want to plant complimentary plants that can support the growth of larval butterflies.
Various beneficial plants can be planted in your butterfly garden. These plants can not only create a visually interesting display of colors and texture but also can support butterflies of all ages.
Consider incorporating any of the below companion plants to create a butterfly garden:
- Eastern Purple Coneflower
- Blackeyed Susan
- Scarlet Beebalm
- Texas Lantana
- Butterfly milkweed
Butterfly bushes are classified as invasive species in many regions of the country.
This classification means they can crowd out native plants, which is harmful to local ecosystems.
Be sure to consult with your local extension office before planting a butterfly bush to ensure that the plant is permitted to grow in your area.
The aggressive growth of the plant can vary slightly with climate. In warmer temperatures, it is considered a weed because it spreads so quickly. In cooler climates, it is better contained, provided that it is pruned properly.
Some cultivars have been developed to be sterile or nearly sterile. Again, check with your local cooperative extension service for insight. They can provide recommendations on what can and cannot be planted in your area.
To check with your local cooperative extension, visit this page on the USDA’s website and scroll to the bottom to find “local extension offices.”
Butterfly bushes are tough, fast-growing plants that can add color to your landscape. They will also attract various pollinators to your yard. Consider creating a butterfly garden with your butterfly bush to support the butterfly life cycle.
These plants are low maintenance. But they are considered invasive in most areas of the country. Because of this, you should check with your local extension office to ensure that they are permitted in your area before planting.
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