Fall cleanup benefits
In cold climates, leaving foliage standing through winter can help protect their crowns. But some perennials really should be cleaned up in fall. Here are three reasons that your perennials might benefit from being cut back in fall. We’ll tell you why it’s a good idea to get rid of old growth, which plants this advice applies to and the best way trim them back.
1. Prevent disease
Some plants harbor pests and disease in their dead foliage over winter. Cut back peonies, above, to keep fungal diseases, such as peony leaf blotch, from spreading. Gather a handful of stems and cut them off 2 to 3 in. above the soil.
Never compost suspicious-looking or infected leaves, stems or flowers. That could spread the problem. Send them away in the trash instead.
Perennials to clean up in fall to prevent disease or insect problems
- Bearded iris Iris hybrids
- Bee balm Monarda didyma
- Blackberry lily Iris domestica
- Garden phlox Phlox paniculata
- Peony Paeonia lactiflora
2. Control reseeding
You can leave plants with seedheads standing for winter interest or to feed the birds. But if you don’t want plants like purple coneflowers to reseed and take over the area, cut them back in fall. Snip spent flowers back just below the mound of foliage for a tidy look.
Perennials to cut back in fall to control reseeding
- Black-eyed Susan Rudbeckia fulgida
- Blanket flower Gaillardia x grandiflora
- Purple coneflower Echinacea purpurea
- Globe thistle Echinops ritro
- Jupiter's beard Centranthus ruber
- Solomon's seal Polygonatum spp.
- Turtlehead Chelone spp.
3. Make room for spring growth
Cutting back some perennials’ fading foliage in fall helps spring-blooming bulbs and perennials. For example, hosta leaves create a dense mat over the ground, which can deform or prevent new spring growth. Don’t cut the leaves all the way to the ground, though. Instead, leave about 2 to 3 in. of each stem standing to protect the crown during winter.
Perennials to clean up in fall to make way for other plants in spring
- Brunnera Brunnera macrophylla
- Hosta Hosta hybrids
- Ligularia Ligularia dentata