A dying center isn't a sign your grass is failing — it's a sign it's ready to become two, three, or four plants instead of one. Dividing ornamental grasses keeps established clumps healthy and vigorous, and it's the easiest way to multiply your favorite varieties without spending another dollar.
Signs It's Time to Divide
- A dead or hollow center. As a clump ages, the middle can die out while the outer ring keeps growing — a classic sign division will help.
- Overcrowding. If the clump is pushing into neighboring plants or has simply outgrown its space, dividing solves the problem and gives you free plants for elsewhere in the garden.
- Reduced vigor. A grass that used to look full and is now thinner or less colorful than it once was often just needs the breathing room division provides.
How Often, by Type
Timing varies more by grass type than most general advice accounts for. Grasses from cooler climates need dividing more frequently than warm-climate varieties.
Cool-Climate Grasses — Every ~3 Years
These congest faster and lose vigor sooner if left too long between divisions.
In our catalog: Carex varieties, Calamagrostis x acutiflora 'Karl Foerster', Festuca glauca, Festuca idahoensis, Sesleria varieties
Warm-Climate Grasses — Infrequent
These can typically go several years longer between divisions without the same drop in vigor.
In our catalog: Miscanthus sinensis, Pennisetum setaceum varieties
When to Divide
Catch the plant just as new growth is starting to emerge — for most grasses, that's early spring. Dividing while the plant is actively growing (rather than fully dormant) means the divisions establish a strong root system quickly instead of struggling to recover. Avoid dividing during the heat of summer or while a grass is in flower.
How to Divide: Step by Step
- Cut back the foliage first. Trim old growth down to about 4-6 inches above the ground. This clears the way and makes the whole process far easier to manage.
- Water the day before. Thoroughly soaking the soil 24-48 hours ahead loosens it for digging and helps protect the roots once they're exposed.
- Dig around the clump. Use a spade to cut a circle several inches outside the visible crown, then work underneath to lift the root ball free.
- Split the clump. For smaller grasses, a sharp spade or even your hands may be enough to pull sections apart. For larger, well-established clumps, two garden forks inserted back-to-back and pried apart work well — or a sharp saw for especially dense, woody root balls.
- Discard the dead center. If the middle of the clump has died out, cut it away and keep only the healthy outer sections with good roots attached.
- Replant promptly. Get divisions back in the ground within a couple of days — the sooner, the better, so roots don't dry out. Water thoroughly after replanting and keep new divisions consistently moist while they re-establish.
What to Do With Your Divisions
Every division is a free plant. Use them to fill thin spots in an existing bed, start a new planting drift elsewhere in the yard, refresh a container, or simply pass extras along to a neighbor. If you're planning to expand a privacy screen or build out a new drift, division is the most budget-friendly way to do it — see our guide on designing with ornamental grasses for ideas on putting new divisions to use.
Not sure if your grass needs dividing or just a seasonal trim? Check our guide on when to cut back ornamental grasses first — cutting back often comes before dividing, not instead of it.