The last week of January to first week of February is the best time to prune ornamental grasses.
New spring growth will not emerge properly and abundantly if plants are not cut timely and severely. You can cut with sharp power or manual hedge shears, or a serrated bread knife.
Cut straight across, parallel with the ground, 3” to 4” above ground. Do not leave a nub, mound, cone, or pouffe, just a straight-across flat top, close to the ground.
You can follow up in late February or early March with a small amount of fertilizer, but be stingy, as excess fertilizer will cause ornamental grasses to grow too succulent and too fast, and they will flop over instead of standing up.
6 Comments on “Trimming Ornamental Grasses”
Should I cut copper plants back now or wait. They have very few leaves on them and are about 3 or 4 ft tall?
Thank you
I would suggest waiting till the first week of February on trimming your copper plants as well. Since copper plants are fairly cold sensitive, you would not want to stimulate new growth by pruning followed by a week of warm weather which might then be damaged by a cold snap in February. There’s always some risk you could get a cold snap in late February Or March but that’s against the odds.
Would you consider liriope grass ornamental? I know I need to cut it back eventually but I was thinking March. Is that too late? And how far back should I cut it? Thanks!
What about lemon grass?
Mine is big and beautiful.
Allison, your lemon grass will look better this summer if you prune hard before spring growth starts. If you’re unwilling to do this because it looks so good now, just prune out browning portions as they occur this summer, and consider a hard pruning at some future pre-spring time.
Brad, liriope is not a grass and does not need to be cut back every year. If you have lots of dead in it that is a reason to cut back and will give you plenty of fresh foliage and get rid of those ugly leaves. But if the plants look pretty good, just leave them alone.