Cutting Back Perennials

Perennials, ornamental grasses, and many ferns look best when cut back annually. The exact timing depends on the plant. Eliminating last year's old growth makes way for succulent new growth. Otherwise you see both dead old and new foliage.

What to cut back

  • Perennials cut backMany perennials put out all new growth from the roots or crown up each season. These will definitely look their best if all of the old season's growth is cut off. Generally this type will have turned brown and ugly by late fall.
  • Other perennials may be evergreen. These won't need to be cut back so severely. Instead they should receive occasional light trimming and thinning, usually during the summer growth and bloom season.
  • Occasionally a perennial may develop a woody branch structure similar to a shrub, for example the tree peony. This branch structure could be pruned but must not be removed entirely as that would essentially ruin the plant.
  • Most ornamental grasses look best if cut back annually.
  • Similarly most ferns should be cut back just like the ornamental grasses.

When to remove the old foliage

  • A simple rule of thumb—do it before new growth starts.
  • But you will want it to look as good as possible until then, so what to do?

Late fall

If the plant looks just plain ugly at the end of the growing season, it's a candidate for cutting back in the fall. Examples:

    Perennials cut back
  • Generally most perennials should be cut back in late fall.
  • Ornamental grasses that look bad. Hint: Most look good over wintering.

Late winter

  • Ferns. If they're going to be cut off, this is the time to do it.
  • Any other ornamental grasses.
  • Anything else.

 

Our service to you

As a landscape maintenance company in Portland Oregon, we've been doing this for several decades now, so we have a pretty good idea of what works best. Because we offer varying service agreements to our customers, you may or may not have a program in place that fulfills the above scenario.

If you wonder, you might look at our serviced agreement with you for appropriately named services, such as:

  • Cut off fern fronds
  • Cut ornamental grasses
  • Cut down perennial tops
  • Perennial maintenance (may include cutting them down)

If you don't have the appropriate service in place already but would like to add it, please contact us so we can make the necessary changes.