When To Cut Back A Butterfly Bush

Butterfly bushes (buddleia) are a species of flowering perennial shrub that grows large, unique-shaped, conical flowers in shades of pink, purple, and blue. As the name would suggest, these bushes are a favorite among butterflies, as well as other pollinators including bees, hummingbirds, and wasps, explains Plant Addicts.

Butterfly bushes are native to Asia, Africa, and America, and grow best in USDA hardiness zones 5 through 9. While there are many species in the buddleia genus, most butterfly bush varieties have a very similar set of care needs: plenty of light, a drink of water when they need it, and occasional fertilizing if grown in a container. Otherwise, they are very hardy and drought-resistant plants, making them a great addition to any garden. The only other specific care requirement for owning a butterfly bush is to prune them once a year to help with both their aesthetic and future growth.

If you've just started to dabble in gardening, you've likely heard the term pruning before, but may not know what it means or why it's necessary. Pruning is simply removing specific branches from a tree or shrub, notes tree service blog Davey. The why, though, is a little more varied case by case.

Pruning trees and shrubs regularly has a variety of benefits. One major advantage of pruning is to keep the plant looking and feeling happy. After a long season of growing and blooming, there are bound to be a few dead or rotten branches. As the plant comes out of its winter dormancy, it shouldn't have to expend more energy than it needs to rebloom. Therefore, getting rid of dead branches will help it refocus its energy toward more new growth. Pruning also gives your shrubs and trees a clean and refined look. Butterfly bushes especially tend to grow a little wild, and pruning can help clean up the overall shape. Even if you prefer more bushy shrubs, you should still prune any offshoots that unnecessarily weigh the plant down.

When it comes to butterfly bushes, there are a few options for when and how to prune them. According to Growing a Greener World, the gorgeous and whimsical flowers only grow on new shrub growth, so many gardeners like to prune back the shrub completely to the ground. A fully mature plant can be pruned down to roughly 12 to 24 inches tall. This preserves some existing height and density but allows the plant to grow lots of new branches ready for the following blooming season.

So when exactly should you carry out this intense pruning? Ideally, it should be done in the early spring after the last threat of frost. Some gardeners swear by pruning during dormant seasons, so you can also prune in late winter. Be very careful pruning in winter, though, as any water inside the stems could freeze and cause the wood to split, in which case you'd have to prune the bush down to the ground.