Find out when to cut back ornamental grasses and the steps to trim them properly.
Marty Baldwin
Ornamental grasses add gentle muted colors, vertical accents, and graceful movement to a landscape.
This guide explains how to time this task right, the best tools and techniques to use.
Credit:Marty Baldwin
Warm-Season vs. Cool-Season Grasses
Ornamental grasses are divided into two broad categories.
Cool-season grasses, such asfescue(Festucaspp.)
andfeather reed grass(Calamagrostisspp.)
Credit:Kritsada Panichgul
do most of their growing in spring and fall when temperatures are between 60 and 75F.
Depending on your climate, some of these grasses may be evergreen, persisting through the winter months.
Warm-season grasses such asswitchgrass(Panicumspp.),fountaingrass(Pennisetumspp.
), and muhly grass (Muhlenbergiaspp.)
do most of their growth in summer when temperatures range between 80 and 95F.
It is much more difficult to selectively remove old growth that is entangled with new shoots.
A consideration for when to cut ornamental grasses back is their appearance.
Others enjoy the colors, movement, and sound that grasses contribute to winter gardens.
Ornamental grasses also provide ahabitat for overwintering birdsthat eat the seeds and use them for shelter.
For small grasses,pruning shearswork well.
For larger grasses a power hedge trimmer or a sharp pruning saw may be needed.
Regardless of the tool you use, wear sturdy glovesleather gloves are bestto protect your hands.
The edges of some grass blades can be quite sharp.
Tall grasses may need to be bound twice, several inches apart.
Step 2: Cut the Grass
Cool-season grasses prefer a less drastic haircut than warm-season grasses.
Cut warm-season grasses back to about 6 inches above the ground.
Its easier to make a neatly clipped mound after the bulk of the stems have been removed.
Only cut cool-season grasses such as feather grass back to one-third of their full height.
Too short a cut can cause permanent damage.
Use a rake to gather up stray stems and clean up the area.
This improves the air circulation and gives the new growth unobstructed room to grow.
Frequently Asked Questions
No.
Leaving the old growth will not usually damage the grass, but it does make it look unsightly.
The combination of old dead foliage mixed with the vibrant new shoots detracts from the overall appearance.
