Butterfly bush is usually planted from potted nursery starts or planted from seeds in the spring. It is a very fast-growing plant that usually reaches its full mature size within a single growing season. Butterfly bush grows well in average, medium moisture, well-drained soil in a full sun location. If planting more than one, space them well apart—5 to 6 feet. Blend in peat moss before planting if the soil is dense and poorly draining. In colder climates, butterfly bush often dies back to the ground in winter and is treated like a herbaceous perennial. In warm climates, they can be pruned back in the same way to keep them under control and stimulate better blooming. Be wary of this plant’s tendency to aggressively spread through self-seeding. Removing the spent flower clusters before they can scatter seeds will help control the plant.
Light
Butterfly bush needs full sun (at least six hours daily) and will become weedy and sparse if grown in shady conditions.
Soil
This plant will thrive in any average, well-drained soil that gets an average amount of moisture. It prefers a soil pH from 6.0 to 7.0, slightly acidic to neutral.
Water
This plant likes a medium-moisture environment and will do poorly at either extreme—intolerant of drought or boggy locations that don’t drain well. They will thrive on 1/2 inch of water by rain or irrigation each week.
Temperature and Humidity
Butterfly bush thrives throughout its hardiness zone range (zones 5 to 9), but expect it to die back to ground level in winter in zones 5 and 6.
Fertilizer
This plant needs no fertilizer, other than a thin layer of compost spread over the root zone each spring.
Types of Butterfly Bush
Butterfly bushes were first brought to England from Asia in 1774 by the botanist Adam Buddle (for whom the plant was named). New natural varieties are still being discovered in remote areas of China and the Himalayas. But most garden plants are named varieties developed by horticulturalists, with names that hint at their color variations: ‘Adonis Blue’, ‘Bicolor’, ‘Buzz Violet Blue’, ‘Pink Delight’, ‘Royal Red’, ‘White Profusion’, ‘Black Night’, etc. However, given the plant’s reputation for invasiveness, responsible gardeners are advised to choose one of the newer non-seeding varieties. For example, here is a list of seedless varieties approved for sale in Oregon, one of several states where standard butterfly bush is outlawed as a dangerous invasive:
Buddleia ‘Asian Moon’Buddleia ‘Blue Chip’Buddleia ‘Blue Chip Jr.‘Buddleia ‘Ice Chip’ (Formerly ‘White Icing’)Buddleia ‘Inspired Pink’Buddleia ‘Pink Micro Chip’Buddleia ‘Purple Haze’FLUTTERBY GRANDÉ™ Blueberry Cobbler Nectar BushFLUTTERBY GRANDÉ™ Peach Cobbler Nectar BushFLUTTERBY GRANDÉ™ Sweet Marmalade Nectar BushFLUTTERBY GRANDÉ™ Tangerine Dream Nectar BushFLUTTERBY GRANDÉ™ Vanilla Nectar BushFLUTTERBY PETITE™ Snow White Nectar BushFLUTTERBY™ Pink Nectar Bush
It is likely that many more seedless varieties will be developed in the future.
Pruning
The spent flower spikes of butterfly bush should be removed promptly after flowering to stimulate continued blooming right up to frost and reduce the chances of self-seeding. This plant grows rapidly, and pruning it all the way to ground level each spring stimulates vigorous growth and profuse flowering. This is often a good idea even in warmer regions where the plant grows as an evergreen shrub.
Propagating Butterfly Bush
It’s rare that you would seek to propagate this bush, since it spreads so readily, but if you do, collecting the seeds heads will give you plenty of seeds to replant wherever you wish (see below). But propagation by seed is not possible if you have wisely chosen a sterile, seedless variety of butterfly bush for your garden. To propagate one of these non-patented varieties, rooting branch cuttings is the best approach. Here’s how to do it:
How to Grow Butterfly Bush From Seed
Butterfly bush self-seeds so readily that “how to do it” is almost laughably obvious. It’s an easy matter to transplant the volunteer seedlings that sprout up around a parent plant. You can also harvest seeds from dried flower heads and store them to plant in the desired location the following spring. More likely, though, you’ll be planting purchased seeds for one of the sterile cultivars now available. In that case, direct sowing the seeds in the desired location will result in germination and sprouting within a few days, and fully mature plants by the end of the first growing season.
Potting and Repotting Butterfly Bush
Most butterfly bush varieties are too large to make good container plants, but there are several dwarf varieties, such as the Lo and Behold and Pugster series that are only about 2 feet tall and make decent container plants. Use a large pot (any material) that is at least twice as deep as the nursery container, and fill it with standard potting mix blended with some compost. In cold winter zones, the potted butterfly bush should be cut down to soil level for the winter and moved into a sheltered location to protect the roots for the winter.
Overwintering
These are sturdy, durable plants that don’t need much in the way of winter protection. Even if the plants die back to the ground due to cold, they will usually assume the role of herbaceous perennial, sprouting up again in the spring. It’s a good idea to cut off flower heads in the fall to prevent self-seeding. In regions where the plant is borderline hardy, a 2- to 3-inch layer of mulch may help protect the roots over the winter.
Common Pests & Plant Diseases
There are no serious pest or disease problems with butterfly bush, although spider mites can be an issue and nematodes can be a problem in the South. Spider mites cause small spots to appear on leaves, gradually causing leaves to turn gray or bronze. Silky webs may also appear on the leaves. Left alone, predatory insects often arrive to keep spider mites in check. Or, you can use horticultural oils or pyrethrin-based insecticides to control them, though be aware that these may also kill the beneficial insects. Nematodes cause yellow patch-like damage to leaves. There is no effective treatment, so affected plants will need to be removed and destroyed.
How to Get Butterfly Bush to Bloom
In moderately good growing conditions (plenty of sun, moist but well-draining soil) butterfly bush will display plenty of flowers from early summer right up to fall. When plants don’t bloom, it’s because of one of these conditions:
Not enough sun. These are sun-loving plants that will not bloom if they don’t get at least six hours of daily sun.Too much or too little water. Butterfly bush likes plenty of moisture, but not sogginess. Excessive moisture can cause root rot which prevents flower buds from forming. And drought can also cause the plant to conserve energy by withholding flowers.Summer is too cool. Butterfly bush thrives in temperatures 75 degrees Fahrenheit or above, and if your summer has been unseasonably cool, the plants may withhold flowers for that year.Planted too deeply. If potted nursery plants are planted too deeply, they may not bloom in their first year, though they usually self-correct by the following season. Plant nursery specimens at the same height they were growing in their containers. Beetle or grasshopper damage. An unusually large infestation of feeding beetles or grasshoppers can devour the flower buds. The plants generally recover for the next year.
Common Problems With Butterfly Bush
The most common complaint with butterfly bush is, without question, its tendency to spread aggressively, even uncontrollably. For many people, the best answer is to remove the plant and replace it with one of the seedless, sterile varieties that are increasingly available. You can minimize the rampant spread by routinely clipping off flower heads before they dry out and scatter seeds, by cutting down all stems at the end of each growing season, and by diligently plucking out the volunteer seedlings as you spot them. Butterfly weed (Asclepias tuberosa) is usually a shorter plant, rarely growing more than 3 feet tall, and it is much more cold-hardy than butterfly bush, suitable to zone 3. The orange or yellow flowers form clusters rather than spikes. Butterfly weed is a common roadside wildflower, but there are also cultivars developed for landscape use. Native to North America, butterfly weed is not considered a foreign invasive, so it is a good choice for native plant enthusiasts.
