When to Reduce Ornamental Grasses

It’s easy to know when to cut back ornamental grass once you know the basics. It’s far more simple than the mowing, watering and fertilizing that may come to mind when thinking about traditional lawns. With ornamental grass, maintenance is far less intensive. Still, you can take actions to make sure your ornamental grasses sail into fall and make it through winter looking sharp.

Watering and Fertilizing Ornamental Grasses

“Many homeowners like ornamental grasses because they are drought tolerant and are rarely bothered by pests,” says Iowa landscape designer Dori Hein. “They seldom need fertilizing either. Fertilizing ornamental grasses may actually cause them to flop over.”

But low maintenance does not equate to no maintenance. “Summer is the best time to keep an eye on watering needs, especially during the plant’s first year while it’s establishing roots,” Dori says. “I like to put down a natural mulch, too, because it mimics natural conditions and feeds the plants as it breaks down. Just don’t put the mulch up against the plant’s base because it can cause the crown to rot.”

When to Cut Back and Divide Ornamental Grasses

Once established, ornamental grasses have few needs. “The big thing with grasses is cutting them back once a year and dividing them once every four or five years,” Dori says.

Most gardeners leave their native grasses in place for winter interest and to provide food for birds. The time when you should cut back ornamental grasses is in late winter or early spring. Cut them back to within a few inches of the ground. “Cut back before the new shoots grow up through the old,” Dori adds, “or you’ll wind up cutting off the new growth, too.” In areas where wildfires are a seasonal concern, cut back grasses in fall to lessen the threat of fire.

You’ll know it’s time to divide grasses when a ring of living grass surrounds a dead center. “It’s easier to divide most grasses when they are still short from their post-winter haircut so there’s no foliage to get in the way,” Dori says. This is also the best time to divide grasses that flower in late summer and fall. Use a sharp spade or root saw and separate the living portion of the grass into smaller sections. Aim for sections that are a little bit bigger than a softball. Replant the sections, water well and enjoy through the seasons.

Ornamental Grass Benefits

Don’t miss out on these ornamental grass perks for your landscape.

• Screen unsightly utilities and other items around the yard.
• Add some privacy by rimming a patio with tall ornamental grasses.
• Soften the harsher look of a structure, fence or corner.
• Create a stage for plants to pop against the grassy backdrop.
• Offer ambiance with the relaxing sights and sounds of grasses swaying in the wind.