When Should I Trim Ornamental Grasses?
Most ornamental grasses can stand through winter, and there are good reasons to leave them alone until spring.
Ornamental grasses are one of the easiest fall chores to postpone. CSU Extension notes that grasses add vertical interest to winter landscapes and are commonly left standing until spring.
For a residential landscape, that often means the best fall maintenance is no maintenance at all.
Why leave them standing?
- The dried stems and seed heads add movement and texture after most flowers are gone.
- Standing material can provide cover and resources for wildlife.
- Waiting avoids unnecessary fall work and makes the spring cleanup easy to time with new growth.
When should they be cut?
For many ornamental grasses, CSU recommends cutting back just before new growth begins in spring. A bundle of stems can be tied together and cut several inches above the crown, making cleanup much easier.
Wear gloves. The leaf edges on some grasses can be surprisingly sharp.
There is one important exception: fire
Dry ornamental grass is combustible. CSU specifically notes that removal may be preferable in public or commercial settings. The same logic applies near structures or in landscapes where wildfire exposure is an important concern. In those locations, winter appearance should be weighed against fuel reduction.
Sources & further reading
These Field Notes translate Colorado horticultural guidance into practical homeowner language. For the underlying recommendations, start with the original CSU Extension resources: