The short answer
No. Most deciduous ornamental grasses benefit from being cut back in late winter or early spring, but not all grasses need it, and some should be treated more gently. Evergreen grasses and grass-like plants such as many sedges are usually combed out rather than cut to the ground. Mondo grass has its own rules; see when to cut back mondo grass.
The right approach depends on whether the grass is warm-season, cool-season or evergreen. If you are unsure which you have, see warm-season vs cool-season ornamental grasses.
Which grasses to cut back, by type
- Warm-season grasses (maiden grass, switchgrass, fountain grass, little bluestem, muhly grass): these turn brown in winter. Cut them back hard, to a few inches above the ground, once they have gone dormant. Many gardeners do it in late winter or early spring, just before new green shoots appear.
- Cool-season grasses (feather reed grass, blue fescue, tufted hair grass, blue oat grass): cut back in very early spring, but leave more behind, often about a third of the foliage, depending on the plant. Cutting these too hard can set them back.
- Evergreen grasses and sedges: don’t shear them to the ground. Comb through the clump with gloved fingers or a rake to pull out dead blades. See evergreen ornamental grasses that stay green all year for more on these.
Specific advice varies a little between sources, which is normal. The common thread: the later in spring you wait, the more careful you need to be not to cut off new growth.
When to cut
Timing guidelines that most nurseries and extension sources agree on:
- Cut warm-season grasses before new growth begins, and do not wait so long that you slice through emerging shoots. Late spring is still acceptable in colder climates, as long as you cut before growth is well under way.
- Cut cool-season grasses as soon as the snow is gone or in very early spring, because they start growing early.
- If your region is fire-prone, trim grasses in fall instead so that dry foliage does not sit near the house.
- In wet, mild climates some gardeners cut earlier (for example, in February) to reduce the risk of rot. See ornamental grasses for the Pacific Northwest.
Leaving the old foliage over winter protects the crown and gives you something to look at. If you want grasses that look good then, our guide to year-round ornamental grasses lists good picks.
How to cut
The steps below are the essentials. Our longer guide to cutting back ornamental grasses compares spring and fall trimming in more depth.
- Wear gloves and long sleeves. The leaf edges of many grasses are sharp.
- Bundle the grass first. Tie the clump with twine, rope or a bungee cord about two-thirds of the way up. This keeps the cuttings together and makes cleanup easy.
- Cut below the tie. For warm-season grasses, a common target is 4 to 6 inches or lower, depending on the plant. For cool-season grasses, leave more, roughly a third of the plant.
- Use the right tool. Hand pruners or shears work for small grasses. Large clumps may need hedge trimmers or a battery-powered trimmer.
- Compost or chop the cuttings. The pieces can go in the compost bin or be chopped and used as mulch.
For small grasses, a rounded “haircut” looks more natural than a flat cut across the top. Taller grasses can be cut straight across.
When not to cut hard
- Evergreen sedges and fescues: combing and light tidying is enough. A hard cut can damage them.
- New plants: go gently in the first year, and just remove dead material.
- Plants with new growth already showing: cut above the green shoots, or comb out the old blades by hand.
If you cut too late or too early
If you cut after new shoots have grown, you will slice off green tips, and those blades will look blunt and brown for a while. The plant will usually recover, but it will look untidy. Cutting too early (in fall) removes winter structure and, in colder areas, may leave the crown more exposed.
If the center of a clump looks dead when you cut it back, that is a sign it needs dividing. See how to care for ornamental grasses and our guide to dividing and transplanting grasses for division steps.
Fall or spring?
Both work for warm-season grasses; spring is the more common choice because it preserves winter interest. For cool-season grasses, spring is usually better. When in doubt, wait until spring and check what the plant looks like. For the autumn side of the question, see what to do with ornamental grass in the fall.