As leaves begin falling and temperatures drop, you might be tempted to cut back your plants, shrubs and trees. But sometimes, pruning does more harm than good. Here’s how to figure out what to chop or when to drop (those shears!):
• Use the right tool. Make sure your pruners are sharp and clean, and if you’re cutting off diseased branches, wash your tool using hot, soapy water or diluted bleach so you don’t spread bacteria.
• Why and how to cut.
Other than fruit trees, most plants don’t require pruning at all, although if your flowering shrubs are overgrown, a good haircut will help them produce more flowers or fruit.
Pruning lets more air and sunlight filter through, which keeps plants healthier. Stick to the dead or dying branches, or ones infested with insects. Cut between the sickly spot and the main part of the plant, making sure to prune back to the main stem so insects and bacteria won’t grow on the stub.
• Thin is in! Don’t lop off the tops of your overgrown shrubs. Thinning them will reduce their size without affecting their shape.
• Not sure when to hack?
Fall is not necessarily the right time to trim shrubs and trees, because pruning stimulates new growth just as these plants are trying to go dormant for the winter. Pruning will weaken them. Instead, trim spring-flowering shrubs like lilacs and spireas in mid-winter or early spring after they’ve blossomed. Hydrangeas, crabapples and junipers can be pruned all winter until the sap flows in the spring. Shrubs like burning bush and barberry can be cut back anytime except late fall, because the new growth won’t have time to harden off before winter. Maples, walnuts, elms and birches will ooze sap when you prune them, so wait until summer.
• Rainy day? Put your shears away. Pruning when it’s wet outside will encourage the growth of microbes and spread disease. Wait until the sun has dried everything out.
• Safety first! If you can’t reach branches from the ground, or are working near power lines, think twice. Pruning can be dangerous, so consider hiring a pro.
• Never remove more than a third of any plant! While some invasive bushes can safely be cut back to the ground, err on the side of caution and stick to the weak parts.
• Got perennials? For plants that don’t have large seedpods, like peonies, bearded irises and monardas, remove dead flowers and the upper third of the stems. Be sure to put down a layer of mulch once the ground is frozen to prevent winter heaving. Plants like hostas, Echinacea and rudbeckia have big seedpods, which attract and feed birds. Leave them alone until the spring’s new growth pops up. Ditto for ornamental grasses. Many perennials, like sedum, add winter interest. As long as your plant has a rigid stem and won’t blow over during Old Man Winter’s winds, leave it be.