“What’s the best way to care for my butterfly bush, now that all the flowers are gone? I usually cut it all the way back in the spring, which usually makes for a beautiful bush throughout the summer. This year, not so much. It was not very full, although it did grow quite tall. Should I be doing something to it in the fall?” Question from Diane of Newark, Ohio
Answer: If you trim the seed heads off of your butterfly bush (Buddleia hybrid) now, you may get a new flush of flowers before season’s end, if the weather stays moderately warm. So, don’t give up on your shrub so early. There are lots of migrating monarchs that still need food for their travels.
Butterfly Bush Pruning Time
There are different fields of thought regarding buddleia pruning time. Some say late spring; others say it does not matter. In my experience, when you hard-prune it back (I generally prune mine back to 1 foot) depends on your hardiness zone. I have pruned mine back in both spring and fall with no difference in summer performance, but my USDA Hardiness Zone 7 garden is milder than yours. So, for your Zone 6 garden, I recommend that you wait until after the last frost of spring to prune buddleia back.
Butterfly Bush Fertilization
For top flowering performance, I recommend that you feed your shrub with bloom-boosting plant food. It should also get full sun for most of the day. Butterfly bushes often don’t live past 20 years, and some of the newer varieties can be shorter-lived. This must also be taken into consideration.
Happy buddleia growing!
Black Gold Horticulturist