When perennials are starting to enter dormancy, after working hard all summer, some gardeners are unsure about what to do with the less than attractive leftover foliage and flowers. Deciding what to cut and what to leave isn’t always straightforward and much depends on your personal preference. These guidelines will help you decide which perennials to cut back and which to leave standing.
Winter Interest and Wildlife:
Evergreens (plants that keep their leaves year round), ornamental grasses, and perennials with seedpods can provide beautiful winter structure. They look gorgeous in the autumn light or with a dusting of frost. You may leave those standing until spring, then cut them back before new shoots appear. Many birds rely on the seed heads of dried perennials for food. Birds, butterflies, and beneficial insects also find shelter in plants stubs and ground covers.
Some examples of plants with attractive features as well as benefits for wildlife include:
- Aster (Symphiotrichum sp.)
- Coneflower (Echinacea sp.)
- Black-eyed Susan (Rudbeckia sp.)
- False Indigo (Baptisia sp.)
- Sedums
- Joe Pye Weed (Eupatorium sp.)
- Sunflower (Helianthemum sp.)
- Ornamental Grasses
- Goldenrod (Solidago sp)
- Milkweed (Asclepias sp.)
Protection From Cold:
Foliage helps to ensure the survival of marginally hardy perennials. These plants are more likely to survive the cold of winter if you leave their tops to collect leaves and snow for insulation and moisture. Just tidy them up in the spring as needed.
Examples of these include:
- Mums (Chrysanthemum)
- Hyssop (Agastache)
- Red Hot Poker (Kniphofia)
- Hardy Geraniums
- Coral Bells (Heuchera)
- Hellebore
- Barrenwort (Epimedium)
- Hardy Carnation (Dianthus)
Disease or Pest Problems:
Cut back any plants with pests or diseases to reduce the chance of infection the following season. Remember to destroy, not compost, diseased stems and leaves.
- Bee Balm (Monarda), Phlox, Lupine, and Columbine (Aquilegia) – are susceptible to powdery mildew and should be cut back to the ground in the fall.
- Hostas – should be cut back and all their leaves removed from the ground as soon as the frost takes them, they harbor slug eggs that will hatch and ruin next year’s greenery.
Personal Preference:
You may choose to cut back plants with browning or blackened foliage and bare stalks that don’t add anything visually to the winter garden. Some examples would be:
- Peonies
- Daylilies (Hemerocallis)
- Siberian Bugloss (Brunnera)
- Speedwell (Veronica)
Some perennials will have new leaves at the base of thier stems in the fall. If you choose to cut these plants back, it’s best to cut off stalks without disturbing this new growth. Such as:
- Yarrow (Achillea)
- Shasta Daisy (Leucanthemum)
- Sea Holly (Eryngium)
Be sure to leave about two inches of any plant you’re cutting back above the soil to mark its location. You will be less likely to dig into them accidentally before they appear in spring if you can see a portion of their stalks!
Unless the plant is diseased or infested with pests, wait until several hard frosts have killed back the tops before you cut back. Allow the roots time to reclaim that energy from the dying plant, keeping it strong for re-emergence in the spring when plants send up energy from their roots to produce beautiful new foliage and blooms.
The more informed you are the better you can decide houw to make your garden our own and maximize the health of your plants.
Happy Gardening!
