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| Figure 1. New England Aster (Symphyotrichum novae-angliae), Showy Goldenrod (Solidago speciosa), Big Bluestem (Andropogon gerardii) supporting each other in a prairie. |
| Gardening with natives often means less garden maintenance throughout the year, which is part of the draw for many of us. However, it also means growing plants that sometimes grow tall and leggy and may flop over without tall or well-rooted neighbors to help support them. Let’s take a look at what’s going on in these circumstances, and the pruning that we can do to help keep them looking tidy. Many plants that grow in mixed communities in the open sun, like some of our favorite prairie wildflowers, are used to growing in competition with other plants. In nature, that means that they’re fighting to grow tall and get as much sunlight as they can or lift their flowers up for the pollinators to find. They also rub “shoulders” with other plants all trying to do the same thing. Without the physical support of that tight crowd, our garden’s plants can start to droop under their own weight. They’re also missing out on a tightly woven network of roots beneath the soil that serve as anchors and keep the plants upright. One way to combat this is to plant your wildflowers within a matrix of other forbes and grasses. Species like Big Bluestem (Andropogon gerardii) and Indian grass (Sorghastrum nutans) would make excellent matrix-planting partners for tall-growing perennials. |
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| Figure 2. Boneset (Eupatorium perfoliatum) growing new stems from a node. |
| Other plants suffer from drooping if they are planted in soil that is too rich for their preferences, or if they are receiving too much shade. They may look like they are leaning towards the light instead of standing up straight and tall. Pruning is a great option for these problems, and it allows you to keep plants happy and upright regardless of why they may be falling down. Often called the “Chelsea Chop” (named for the timing of the Chelsea Flower Show in England) or the “June Whack-back,” cutting back summer and fall blooming perennials has a number of benefits. Taking ⅓ to ½ off of the plant can help control its ultimate height, which in turn helps prevent falling or flopping. The resulting growth will likely be bushier than the original, and you may even get more flowers this way. It may also delay blooming a bit, providing flowers later into the season. Cutting back your plants in tiers from front to back can achieve a layered effect, with the taller stems in the back flowering before the shorter stems in the front. When making the cuts themselves, make sure that you cut above a node (the point where a leaf grows off of the stem). The plant should be able to grow new stems from the axillary bud that lies just above the node. Make the cut at a 45-degree angle to help prevent water from collecting on or in the open stem, and you’re good to go! For new gardeners, and especially for those looking to replicate nature in their gardens, it is easy to be hesitant about cutting back perennials. This process seems unnatural, but there’s nothing to worry about. With the exception of deer and rabbits (that we generally try to prevent from damaging our plants), our garden’s flowers aren’t being grazed upon, tread upon, or exposed to any number of other damaging events. In a natural setting, these same plants are constantly exposed to damage and recover as well as they can and may not achieve their full heights. They are also being crowded and shaded by their neighbors, which also limits their size somewhat when compared to specimen plantings in a garden. So, now that we know what to do and why we might do it, which perennials does this apply to? Summer blooming plants like Oswego Tee (Monarda didyma), Tall Garden Phlox (Phlox paniculata), or Prairie Coneflower (Ratibida pinnata) do well with a cut back. Options that bloom in the fall like Asters (Symphyotrichum spp.) and Goldenrods (Solidago sp.) can also be kept in check this way. What you’re looking for are plants that don’t have flower buds yet and bloom after spring. Some plants like Dense Blazing Stars (Liatris spicata) don’t grow upright stems until they are getting ready to flower, so they aren’t a good candidate for cutting back. Hopefully, this gives you some ideas on how to help manage your tallest perennials, and some confidence to know that your plants may reward you with an abundance of flowers and improved posture in your garden! |
June 2023 Newsletter
