Landscape Journal Begins: Cutting Back

When we give presentations, people always ask questions about managing grasses in the landscape. When should they be cut back? When is the best time to plant? We’ve been growing grasses for decades, but there are always new questions about working with them in the landscape. That’s why we’re starting a new, monthly blog series written for landscape professionals.

In Landscape Journal, we’ll show you our gardens and share our experiences in landscape management. We’ll also introduce you to or reacquaint you with some great, garden-worthy grasses. And you can help guide us toward answering your questions.

Plantings around our nursery serve as demonstration gardens and make the nursery a pleasant place to work and visit. We’ve been stepping up our landscape game recently with the help of our gardening team of Kata Kreß Wallace and Mark May. Kata grew up in the nursery industry—her father owns Sarastro Stauden, a perennial plant nursery in Austria. Mark has more than 30 years of professional landscaping experience. With Kata, Mark, and the rest of the Hoffman Nursery team, we draw on a large reservoir of knowledge. We also hope to reach out to others in the industry for their thoughts and advice.

Cutting back too close to the crown, especially with a mower, can damage growing points and make the grass more vulnerable to pathogens.
Cutting back too close to the crown, especially with a mower, can damage growing points and make the grass more vulnerable to pathogens.

This time of the year, landscape cleanup and cutback jump to mind. In the Southeast, it can be the perfect time to cut back grasses. Cool season grasses and sedges have just started new growth, and warm season grasses haven’t started yet. In cooler climates, keep an eye out for any new growth. You’ll want to cut grasses and sedges early enough that you don’t snip off the new growing tips. Sedges recover from cutback more slowly than grasses, so you can decide whether to cut them back based on looks. If they’re shabby and tired-looking, you can cut them back. But you can also leave them and let new growth come out and cover the old.

Scheduling and labor availability are big considerations in cutting back, but other factors play a role, too. Anne Spafford, Associate Professor of Horticultural Science at North Carolina State University, suggests we consider pollinators in our cleanup plans. Native bees often overwinter in the hollow stems of grasses. She suggests waiting until bees emerge from hibernation and become active before cutting back grasses. That wakeup happens when average temperatures reach 57°F (14° C). In the Southeast, that’s around mid-April. In colder climates, it’s even later.

There are downsides to waiting that late: grasses will already have pushed up new growth and landscape crews are crazy busy. But if you can wait until later to cut back, you’ll be providing important habitat for bees. If you do cut back later, we suggest cutting higher to avoid the new growing tips. Most of the time, new growth will cover up the old foliage and look just fine.

Another approach is to find middle ground. How about leaving a few grasses uncut, so that native bees and other wildlife can get more benefits? You can rotate what you cut back each year so that a portion of the landscape is devoted to supporting wildlife. There’s no “right” answer on when to cut back, but you can make choices that match your goals and constraints.

Having help available in late winter plays a big factor in when we cut back and clean up many of our garden areas.
Having help available in late winter plays a big factor in when we cut back and clean up many of our garden areas.

We cut back our 1,300-foot-long, roadside border last month when we had student groups available to help. There are more remote areas of the nursery where we leave the plantings and only cut back every few years.

Once you decide when to cut back, there are different techniques to it. With our large border, one person cut back the grasses and perennials with powered hedge trimmers, while helpers raked the cuttings and loaded them on a trailer. We compost the cuttings in a separate pile, but you can also leave them in place to decompose.

We use electric hedges trimmers on taller, thicker grasses. With shorter species, the hedge trimmer or even a lawn mower will work. If you’re using short grasses or sedges as a groundcover, the mower is a snap. Using a mower helps add organic matter to the bed. You can always use hand pruners, but with large-scale landscapes, hedge trimmers or a lawn mower are far more efficient.

We hope this discussion gets you thinking about your landscapes. Thanks for reading! Please join us the first week of each month for more Landscape Journal.

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