An important landscape management step for perennial flowers is pinching and pruning – for 2 reasons – to keep them looking good and to keep them healthy. Which perennials? Most of them, actually, salvia, yarrow, astilbe, coral bells, catmint, shasta daisy, anemone, verbena, goatsbeard and certain annuals such as petunia, snapdragon, coleus, zinnia and lantana.
Most gardeners look at perennials that have finished blooming for the year and think, “oh my gosh, they look ratty and are overgrown.” A few more botanically oriented souls might simply observe that they’ve just gone through a life cycle change, but most folks object to the fading flowers and leggy stems and are looking for a recommendation on what to do next.
The second reason for cutting back after blooming is to channel the energy produced – the carbohydrates and sugars – into the roots rather than into the faded flower stems and developing seeds.
The key to success is where to cut them. Removing the fading stem tissue just above a new growing point will address both reasons for removal – to groom and to promote vigor in the plants. The same grooming and energy re-channeling holds for roses as well; cut these faded flowers and stems off the plant just above where a 5 leaf leaflet joins the stem.
Following cutting, toss the removed portions of the plant on your compost pile and mix it with other green waste such as grass clippings and the broccoli stems that your kids won’t eat.