When to Cut Back Ornamental Grasses

“In the fall, many of the ornamental grasses that looked so nice over the summer are beginning to look a little shabby and worn. Can they be cut back now, or should I wait until colder weather?” -Bill

Traditionally, ornamental grasses are cut back in the late winter or early spring, for two main reasons:

  • The dormant foliage provides some winter interest in an otherwise bare garden.
  • The foliage provides some insulating protection from cold and soaking rains.

The cold protection is important if you are planting grasses only marginally hardy to your zone. Leaving the foliage over the winter can insulate the plant and increase its chances of surviving the winter. The foliage also shields water from the crown, helping to prevent rot.

If you live in a warmer climate, or if you are planting grasses that are winter hardy in your zone, when to cut them back is really a matter of preference. Some gardeners like the “neat and tidy” look over the winter, while others like the swaying and crackling grasses in the landscape. In warmer areas, cutting grasses back in the fall can actually stimulate next year’s growth, giving you an early start next season.

Julie

5 COMMENTS

  1. That is very useful information Julie and brings up another question related to preparing our garden for winter. We live on the Gulf of Mexico and one of the popular plants in this area is the African Iris because they bloom from spring through fall. Should the old foliage be cut back in winter like regular iris?

  2. No – African Iris blooms more than once on the same flower stalk, so it shouldn’t be cut back. Just remove any dead parts. Good luck!

  3. Julie, I live in Chicago area and have already cut back my ornamental grasses. While I now realize this may have been in error, is there anything I should do to protect them throughout the winter?

  4. Jerry, if the grasses are fully hardy in your area, they should be fine – when to cut them is really a matter of preference. Insulation is more important if you’re trying to grow grasses that can be killed by freezing temperatures.

    For extra protection of tender grasses, you can spread some evergreen boughs over the crown of the plant to help insulate and shed water. This will help prevent crown rot and is a great way to recycle holiday greenery, too.

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