Butterfly Bush Is the Perfect Shrub, Except That It Can Become a Terrible Weed
When you're ready to add something new to your landscape, take a moment and think about all the qualities in an ornamental plant that you might want. Chances are, you'd list qualities such as beautiful flowers, excellent resistance to diseases and pests, attractive to hummingbirds, and butterflies, and quick growth with very little fuss. Well, butterfly bush fits this description, which is probably why it's become such a popular choice for gardens across the country. But it has a major drawback: It reseeds like crazy. In fact, it has been declared "noxious" by both Washington and Oregon where it can longer be sold because it spreads so aggressively. Fortunately, you've got a few options for growing this plant responsibly.
Butterfly bush, a native of China, seemingly has it all. Flowers range in colors from purple, pink, white, to orange and they attract all kinds of wildlife. Some cultivars even produce a wonderful honey-scented fragrance that wafts through the breeze. Sizes range from minuscule dwarves to giants over nine feet tall and in warmer climates, they'll maintain their leaves throughout the winter. But that's about where their appeal stops and their negative attributes begin to outweigh the positives.
You see, with all those beautiful flowers attracting scads of pollinators to your garden, come thousands of tiny seeds from which thousands of tiny plants will grow and flourish. In its preferred Hardiness Zones 5-9, butterfly bushes will quickly outcompete slower growing native species and although they provide copious amounts of nectar, the rest of the plant is inedible to native insects. Even hungry deer will leave it alone! Before long, butterfly bushes will begin popping up across the yard and neighborhood, eventually making their way to disturbed fields and along waterways. Beautiful to the human eye, yes, but they offer nothing for the hungry caterpillars that turn into the butterflies we all love.
So, let's say you just have to plant a butterfly bush. You love that sweet honey fragrance and those abundant spikes of colorful tiny flowers, despite the species' potential for invading your native ecosystem. Fortunately, you have a few options.
Your first option is to keep your pruners close by when your butterfly bush starts blooming. Instead of letting your plants go to seed—you'll know it when the flower spikes begin to fade and turn brown—cut off the flowers before they've begun releasing seeds. Simple, really, but considering they'll produce thousands of flowers from the beginning of summer through fall, you'll have your work cut out for you.
To save yourself of yet another chore in the yard, a second option now exists, thanks to the breeders developing new varieties of plants for us to grow in our yards. This option is to buy sterile (over 90% sterile, anyway) selections that will drastically lessen the odds of your plants producing viable seed. Proven Winners offers a series called Lo & Behold, which are a collection of dwarf cultivars, while Ball Seed has released the Flutterby collection, offering both traditionally-sized plants and more compact options. The downside? They're all still potentially invasive unless you're quick with your pruners after they bloom.
Your third option is to not plant butterfly bush at all, but instead, plant a native species like orange woolly butterfly bush or Utah butterfly bush, both of which grow in warmer regions. Although less showy than the non-native species, they do have gorgeous silvery foliage and won't spread aggressively. More hardy native alternatives that will produce abundant showy flowers that draw pollinators include sweet pepperbush (Clethra alnifolia) and Joe Pye weed.