Butterfly bushes (Buddleia) are easily one of the most popular flowering shrubs out there, and for good reason—they keep your patio and garden looking gorgeous all summer long. But if you want those stunning blooms to return year after year, you might be wondering: how do I make sure my butterfly bush survives the winter?
How does a butterfly bush handle the cold?
Most varieties are actually pretty tough and can handle temperatures down to about -5°F, but here’s the catch: they usually need to be about five years old before they reach that level of hardiness. For younger plants, a little extra winter protection around the roots is a must. Don’t panic if you see some die-back on the branches during a cold snap; it’s totally normal. You’ll just prune those away in the spring. Since these beauties bloom on “new wood” (this year’s growth), they’ll bounce back just fine. To give them the best start for spring, spread a thick layer of mulch over the root zone in late fall.
With the right TLC, your plant will grow strong enough to handle winter with just a bit of help. Here’s my checklist for a healthy, resilient shrub:
- Pick a sunny spot that’s protected from harsh winds.
- Feed your plant with some good compost before the new growth starts in spring.
- Prune old branches back to about 12 inches. One exception: *Buddleja alternifolia* blooms on old wood, so only thin out the oldest branches on that one.
- If you can, plant some groundcover around the base—it acts as a natural thermal blanket.
- Deadhead those spent flowers regularly to keep the plant from putting all its energy into seeds.
- Always mulch the root area before the first big freeze hits.
Caring for potted butterfly bushes
If you’re growing your butterfly bush in a container, you’ve got to be a bit more careful. Because the soil in a pot can freeze all the way through, the roots are much more vulnerable. Ideally, you should move your pots into a bright, frost-free room for the winter. If you don’t have the space indoors, you can keep the pot outside, but you’ll need to bundle it up! Place the pot on an insulated base (like a thick piece of wood or Styrofoam) and wrap the container in bubble wrap, burlap, or garden fleece. Top off the soil with a heavy layer of mulch and tuck the pot into a sheltered corner near the house.
Hardy vs. frost-sensitive varieties
There are plenty of cold-hardy varieties that do great in most American gardens. Some of my favorites include:
- ‘African Queen’ (stunning purple-violet spikes)
- ‘Black Knight’ (deep, dark purple blooms)
- ‘Dart’s Ornamental White’ (crisp, clean white flowers)
- ‘Purple Emperor’ (rich mauve-red clusters)
- ‘Pink Delight’ (beautiful true-pink blooms)
Just keep in mind that not all butterfly bushes are built for the cold. Varieties like the Globe Butterfly Bush (*Buddleja globosa*), *Buddleja colvillei*, and the Yellow Butterfly Bush are much more sensitive to frost. These types should definitely stay in containers so you can bring them somewhere warm when the temperature drops.