I have a question about my butterfly bush. I have read not to prune it back until early spring, and then again I hear to prune it to the ground in the winter. What is the best approach? Also do Butterfly bushes need to be pruned every year and is it too late? We pruned our bushes last year and they were beautiful but took forever to get tall again. I would like them to fill an area in our yard and would like to know the best way to care for them.
Regarding your butterfly bush (Buddlia), you are safe to prune it at either time as long as it is late winter moving into early spring. As a matter of fact you can prune them any time of the year except early winter. The reason being, the stems are hollow and any water that accumulates in the stem and subsequently freezes will cause the wood to split. That’s not a good thing. Butterfly bushes bloom on new wood so as long as you have plenty of sun light, you’ll get lots of blooms throughout the summer by pruning in the spring.
Butterfly bushes do not need to be pruned every year. In fact, you only need to prune them when they get too large for the space allotted. But since butterfly bushes only bloom on new growth many gardeners prune them severely each spring to encourage lots of new growth and lots of flowers.
I would advise that you prune this shrub back to twelve or twenty-four inches high. That way, you retain some of the growth from last year which will fill in that area of your yard more quickly and provide you with plenty of flowers. Remove the spent blooms periodically during the summer to encourage additional new growth and subsequent flowers until frost.
If they have already started to leaf out, you can still prune them back some, but if you prune below new shoots, it will take much longer for it to fill out this year. A fertilizer application in March or April and again in June or July will help to encourage growth. Use a tablespoon of 10-10-10 for each foot of height and sprinkle it around the shrub out to the drip line.