If your ornamental grass has developed a dead center or you’d like to add more plants to your landscape for free, it’s time to divide them. In this guide, we’ll show you how to divide and propagate ornamental grasses, step-by-step.
Spring is the best time to divide ornamental grass, just as new growth is emerging. If your grass has a hollow center or dead grass surrounded by new growth, grab a shovel to dig up the clump and a sharp, sturdy tool to slice through the dense roots.
Once you’ve divided your plant, follow our tips on How to Care for Ornamental Grass to help each new clump establish and thrive.
Step 1: Cut back the grass
Before you start dividing and digging holes in your garden, cut back the grass. Spring is the best time to cut back ornamental grass, before new growth appears and after the last frost.
Check out our guide on How to Cut Back Ornamental Grasses to ensure easy spring cleanup and proper cutting height.
Some gardeners prefer to divide their ornamental grass the same day they cut back (it’s a convenient way to feed two birds with one scone).
However, wait to divide until new growth is just emerging in spring, recommends Aaron Steil, Consumer Horticulture Extension specialist at Iowa State University Extension and Outreach.
“Some ornamental grasses develop a dead center as they age,” Steil says. “Waiting until the foliage begins to emerge allows you to see and remove this dead area when splitting the clump into pieces.”
Step 2: Soften the soil
Water the soil one to two days before you divide. This will help to loosen any dry soil, making division significantly easier.
Step 3: Dig up the clump
The grass is cut and the soil is prepped. Time to divide.
How you dig up the clump depends on size and preference. If it’s a large clump that can be divided into multiple pieces, you may want to dig up small sections at a time. Digging up the whole clump may be difficult to manage.
If it’s a small clump, you can slice the clump in half with a shovel and remove one half from the soil, or you can dig up the entire clump if you prefer.
When removing parts or all of the clump from the ground, slice through the soil 6 to 8 inches deep so that you get the roots. If you dig up the clump without the roots, the divided pieces will struggle to establish in their new location.
Step 4: Split the roots
“The root systems of ornamental grasses can be dense and fibrous,” says Steil. “If a sharp spade doesn’t seem to cut it, try a reciprocating saw. These power tools can make quick work of this tough job.”
Slice the root ball into the desired amount of pieces you would like to propagate, removing dead portions of the plant as you go. If the clump is particularly large, you might find yourself with as many as eight new pieces to replant.
Step 5: Replant
In the spots where you want to replant the clumps, dig holes as deep as the root ball. Set each divided plant into its hole, then backfill with the soil you removed, stopping at the base of the plant. Be careful not to mound the soil too high over the crown, since that can smother growth.
| Tip: Choose sunny, well-ventilated locations. Ornamental grasses struggle in heavy shade or areas with poor airflow. |
Step 6: Water
Water your newly planted ornamental grass generously to encourage a deep root system. David Lowenstein, Consumer Horticulture Extension Educator with Michigan State University Extension, recommends watering newly planted ornamental grass gardens with 1 inch of water per week in the first month to month and a half.
Once the grass is established, your watering chores will lighten. “In their second and future years, they should not require any supplemental watering. Most grasses and sedges have deep roots and tolerate drought conditions,” says Lowenstein.
Step 7: Mulch
Lowenstein recommends following up with 2 to 3 inches of mulch to the garden bed to suppress weed growth. However, if the garden doesn’t experience weed growth, then you can skip mulching, he says.
| Pro Tip: Keep the mulch 2 to 3 inches away from the base of the plant. Otherwise, the mulch may suffocate new growth. |
To determine how much mulch you need and which type is best for your landscape, check out our guide on how to mulch.
FAQ about how to divide ornamental grass
As long as the division has roots, the plant is likely to establish. If you’re concerned your small division may struggle, consider planting it in a container so that you can monitor and control its growing conditions.
Divide your ornamental grass every two to five years or when you see dieback in the middle of the clump.
For divisions that you can’t plant immediately, grow them in a potting container with good drainage until you’re ready to plant them in the ground.
Hire a lawn care pro
As you prepare to cut back and divide your ornamental grass, your landscape is likely blossoming with other spring chores. The lawn needs mowing, the soil needs fertilizing, and the weeds need controlling.
Hire a lawn care professional through lawn love to mow, fertilize, and control weeds in the lawn so that you can focus on your garden beds and exercise your green thumb.
Main Image: Dividing ornamental grasses for replanting in spring garden. Photo Credit: Светлана Мищенко / Adobe Stock
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