What perennials should you cut back in autumn & which add winter interest?

heuchera in Amherst
Heuchera is one of the perennials you shouldn’t cut back in the fall. Photo by Connie Oswald Stofko

There are still lots of things you can do in the garden now. The Master Gardeners of Erie County have posted new articles in WNY Gardening Matters, including one on what to do in the garden in October.

One of the tasks addressed was cutting back perennials.

For winter interest, many gardeners like to leave rudbeckia, butterfly weed, mums, heuchera and grasses standing, said author Peggy Koppmann.

But there are some perennials that just get ugly after frost and are susceptible to disease. Here are some that should be cut back:

  • Iris (reduce cover for borers and fungal diseases)
  • Monarda (cut back if powdery mildew is present)
  • Columbine (disease management, early spring growth)
  • Gallardia (improves plant vigor)
  • Peony (remove infected foliage)
  • Veronica (will turn black and ugly)
  • Salvia (cut back to new basal growth)

The article on what to do in October offers many other tasks you can do now.

Other articles in WNY Gardening Matters include:

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11 Comments on “What perennials should you cut back in autumn & which add winter interest?

  1. I would cut back the hostas after frost because they look unattractive. In general, I like the rule, “if it stands up, leave it”. I also prefer not to cut back anything green.

  2. Connie, I recently purchased 2 catmint perennials for the purple flowers that are promised but now I am hesitant as to where to plant them as I read online that they will draw cats which I do not want to attract to my flower beds, not even my property. Will they invite a nuniance? Should I plant them on the outer perimeter of my property?

  3. I have a border of about 10 feet of catmint. There are lots of stray cats around, they don’t bother it at all.

  4. Pat, David Clark gave a very detailed answer to this question on another post. You can see his explanation in the comments section on the article How to overwinter tuberous begonias. See it here.

  5. I have an oak leaf hydrangea, planted about 4 years ago. It has yet to flower. In the past, with “regular” hydrangeas, I always cut back late fall/early winter with great success the following spring. But this one doesn’t do well not matter what (one year I cut it back in the fall & it came back nice & leafy the following spring but no flowers; the next year I just left it there & it looked scraggly the following spring – still no flowers.) Thoughts?

  6. Lots of good questions!
    I agree that hostas should be cut back after the leaves fade. If you leave some of the flower stems up they will persist over the winter and you will be able to tell where the hostas are next spring. they are late to come up so this avoids digging where they are.

    Escargo Begonias make great house plants. Keep them on the dry side to avoid fungus.

    Usually Oak Leaf Hydrangeas don’t require pruning. If they are not blooming check the amount of sun, water and soil pH.

  7. I let my cone flowers alone when their seed buds dry. The finches that stay around and other birds, too, love them. And it also a source of food when the snows come.

  8. Technically the soil and air temps are warm enough to move plants but we have no way of knowing how soon the cold weather will come. Personally I stopped moving things a few weeks ago.

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