Cut back an ornamental grass at the wrong time and you can lose the very thing you planted it for — winter structure, seed heads, or simply a healthy plant come spring. The right timing depends entirely on what kind of grass you're working with, since cool-season, warm-season, and evergreen types all play by different rules.
The Short Answer
For almost every grass in this guide, late winter to early spring — before new growth emerges — is the right time to cut back. The narrow window matters: cut too early and you lose winter interest and wildlife habitat; cut too late and you risk damaging the tender new shoots already coming up underneath the old growth.
Know Your Grass Type First
Ornamental grasses fall into three broad categories, and each one gets a different approach.
Warm-Season Grasses
These grow most actively in the heat of summer and go dormant — turning brown — once temperatures drop in fall. Cut these back hard, to about 4-6 inches above the ground, in late winter or early spring before new growth starts. Hedge shears, a hand sickle, or a string trimmer all work; bundling the clump with twine first makes a clean cut much easier on tall, dense varieties.
In our catalog: Miscanthus sinensis 'Morning Light', Pennisetum setaceum 'Fireworks' & 'Rubrum'
Cool-Season Grasses
These actually grow in spring and fall and tend to hold color better through winter than warm-season types. They're more delicate — skip the hard cut-to-the-ground approach and instead give them a light trim or simply comb out dead, dry blades by hand. Cutting too harshly can genuinely damage the plant.
In our catalog: Festuca glauca varieties (Blue Fescue), Calamagrostis x acutiflora 'Karl Foerster'
Evergreen Grasses & Grass-Likes
Many sedges, along with Phormium, Cordyline, and similar grass-like plants, stay green year-round in mild climates and don't need an annual hard cutback at all. Instead, gently rake or comb through the foliage each spring to remove old, dead, or matted material and improve air circulation. Every few years, a more substantial trim — removing up to two-thirds of the old growth — can give the plant a fresh start.
In our catalog: Carex varieties, Liriope, Ophiopogon, Phormium, Cordyline
How to Cut Back: Step by Step
- Watch for new shoots. Small green growth emerging at the base of the plant is your sign that it's time — and that you shouldn't wait much longer.
- Gather and bundle. For larger clumps, wrap twine, tape, or a bungee cord around the foliage to pull it into a tight bundle before cutting. This makes for a cleaner cut and an easier cleanup.
- Cut low, but not at the crown. For warm-season grasses, cut to roughly 4-6 inches above the ground — low enough to clear out the old growth, but without cutting into the crown itself.
- Clear out the dead center. Once the bulk is cut, reach into the remaining clump and pull out any loose, dead, or matted material. This opens the plant up to light and air, which speeds up healthy regrowth.
- Compost the trimmings. Cut grass makes good mulch or compost material — just avoid burning it, which isn't good for you or your garden.
A Note on Climate & Zone
Exact timing shifts with your climate. Gardeners in milder, southern zones often cut back as early as January; colder, northern zones may not see the right window until March or even April. The rule that matters more than the calendar date: cut once you see the ground thawing and new shoots emerging, not before.
Curious which of your grasses needs dividing instead of just cutting back? Check our guide on dividing ornamental grasses, or browse our full grass catalog if you're planning new additions for next season.