Tips for growing butterfly bushes. Care and propagation info and plants you can buy. Orange, red, and yellow cultivars. Purple Emperor and Blue Adonis butterfly bush plants.
Dwarf varieties mature to a height lower than 4 feet. They are useful in small yards or large pots where the large cultivars simply would not fit. If this is your situation, there is a similar plant you might also consider: the dwarf crape myrtle.
The plants below are the larger types. Most cultivars grow from 5 to 15 feet in height and equally as wide. The arching branches of these summer-blooming plants are clad in large, tapering, and coarsely textured leaves which sometimes feature an attractive bluish or silvery cast.
Despite these alluring attributes, the foliage is not what gardeners love about butterfly bushes; the abundant 10 inch flower clusters are the big draw for humans and butterflies alike. Hummingbirds also sip nectar from the blooms.
The lightly scented flower spikes bloom from the bottom up, and each tiny blossom is dotted with an orange eye. This is why Buddleia davadii is sometimes called the orange-eye butterfly bush.
When to Prune: In warm winter areas where the stems do not die back, butterfly bushes should be trimmed each spring to neaten them and to keep the plants from growing too large.
How: Cut them back to within a foot of the ground before new growth begins.
In the coldest end of its range, the frost will perform this chore for you. Trim off the spent blooms to extend the bloom season.
You can allow the shrubs to grow sans pruning, but the flower clusters will be smaller.
Propagation: Take 6 inch tip cuttings in the spring, prior to bloom. Strike them in a peat-based potting mix.
Purple butterfly bush used as part of a mixed shrub border.
Install taller varieties at the back of a shrub or perennial border. Place dwarf types at the front or middle, or better yet, plant them in pots and use them to fill gaps that form during the growing season.
As you can see from the image above, B. davidii is especially fetching when mingling with roses. Where space allows, massed plants will form a striking focal point from July till the first frost.
When grown throughout most of its range, B. davidii is a woody shrub which will live for many years. In cold areas, it performs more like a perennial, dying to the ground each winter and returning reliably each spring.
In Central Florida, we cultivate it as an annual. Our notoriously inorganic soil does not support longevity in this species. Plants will thrive in it for a season or three and then suddenly decline and die.