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.
Brandi says
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!
Allison Carolyn says
What about lemon grass?
Mine is big and beautiful.
james says
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.