How to Grow Buddleia (Butterfly Bush)

This flowering shrub is perfect for attracting bees and butterflies

Close-up image of a flowering Buddleia (butterfly bush)

Jacky Parker Photography / Getty Images

The Buddleia is a deciduous, vibrant flowering shrub that is well known for attracting pollinators in sunny gardens with fertile soil. This is why it gets its alternate name of the Butterfly Bush.

These shrubs are easy to grow, bloom impressively throughout the summer, and have low-maintenance care requirements. The Buddleia comes in a wide selection of varieties and cultivars. The one you select will depend on the size of your garden and the space you have available. Some can grow up to 12 foot tall.

It's worth noting, however, that the Butterfly Bush is considered an invasive species and can grow out of control rapidly if the right measures aren't taken.

Botanical Name Buddleia davidii
Common Name Buddleia, Butterfly Bush
Plant Type Perennial, deciduous shrub
Mature Size Up to 12 foot
Sun Exposure Full sun
Soil Type Can cope in a variety of well-drained soils
Soil pH 5 to 8
Bloom Time Summer
Flower Color Wide variety
Hardiness Zones 5 to 9
Native Area China

How to Grow Buddleia

To encourage the best growth and impressive blooms, your Buddleia will need a full sun position in well-drained soil. Annual deadheading and pruning will help your Buddleia retain their best shape, most full bloom, and will prevent this fast-growing shrub from getting out of control.

Light

Buddleias love sun, and they'll flourish in a position where they can benefit from a full day's direct basking. They can manage in partial sun too, but you might find they don't bloom as impressively.

Soil

Providing they get enough sun, Buddleias are resilient shrubs and cope with a wide variety of soil types. You just need to make sure that it's well-drained. Otherwise, you could find that the roots begin to rot.

Water

Generally, you'll want to water your Butterfly Bush sparingly. They're a drought-tolerant shrub and don't do well in water-logged soils.

During their initial growth period, they'll require more regular watering—just be careful not to over-soak the soil. If the temperatures soar, a thorough once a week watering for a mature plant will be beneficial.

Temperature and Humidity

The Butterfly Bush is tolerant of a wide range of temperatures. If you experience colder winters, it'll die above ground, but you can expect good regrowth in the spring.

If you live in a more temperate climate with very mild winters, you can expect the shrub to remain semi-evergreen. Very hot, dry summer temperatures will impact on the success of the bloom. In particularly hot regions, the Butterfly Bush has more impressive flowering in spring and fall.

Fertilizer

This hardy shrub doesn't need fertilizer to do well. In fact, using it can result in too much leaf growth and a reduced amount of flowering.

Propagating Buddleia

Taking a softwood cutting from your Buddleia in spring is the preferred option for propagation. They tend to root more easily and grow more successfully.

Make sure you take your four to five-inch cutting from fresh growth when the shrub is well hydrated. Cutting at an angle will help nutrients to be absorbed most efficiently.

It can help to dip the cutting in rooting hormone before popping into moist potting soil. The cuttings should be positioned in a partial sun position. Too much intense light can burn the new foliage. Root development usually starts within a couple of weeks, but it can take up to six weeks before they're ready to be transferred.

Longer semi-hard or hardwood cuttings can also be taken in the fall or winter, although they don't always establish as well.

Varieties of Buddleia

There are a wide selection of different Buddleia varieties. They can vary considerably in their size and colors. If you want to avoid your Buddleia overtaking the native species in your garden, you might want to look for a seedless cultivar.

Just a few of the available types of Buddleia are listed below:

Pruning

If you have selected a large Butterfly Bush variety, hard pruning in late spring will help to ensure the shrub doesn't get out of control. Taking the stems back to around a foot in length is recommended. Just make sure you don't undertake this task until the last of the extreme cold weather has passed.

Don't be tempted to prune in the fall as this can kill the plant off.

Pruning doesn't just ensure that rangy varieties of Buddleia don't become too extensive. It also means that your shrub will retain its vigor and you'll see a better bloom in the summer.

Regular deadheading is also recommended. This means you're less likely to have unwanted new shrubs sprouting in your garden from naturally dispersed seeds.

Being Grown in Containers

If you want to grow Buddleia in containers, you'll need to make sure you select a generous and heavy pot size. Some types will just be too big for containers, so chose the species carefully. Container grown Buddleia need more frequent watering than those planted directly into the ground. In the warm weather, a watering every other day may be needed.

Pick a lightweight, easy draining potting soil. Garden soil can be too heavy and compact for a pot. You should also select a well-lit position for your pot where you won't have to move it often.

Often container-grown Buddleia need to be transferred to the ground in their second year as their rooting system and size won't tend to work in a limited container anymore.

Growing From Seeds

Buddleia seeds require a short cold stratification period of around four weeks. These shrubs are easy to grow from seeds, and, because they're fast developing, you may even be lucky to experience a full bloom in their first year.

You can sow the seeds indoors at any time of year in a porous, not overly-moist soil. Don't sow too deeply, and keep them in a warm and well-lit position.

The seedlings can be transplanted outdoors in late spring.