As the gardening season concludes, perennials may begin dropping leaves and entering dormancy. This natural process often prompts gardeners to question whether to cut back their perennials or leave them as they are for the winter.
The best approach depends on the specific plants and regional climate conditions.
- In colder areas, leaving the foliage standing can protect the plant crowns from harsh winter weather, providing insulation and safeguarding against snow.
- Conversely, some plants benefit from being cut back in the fall to prevent diseases and prepare for easier growth in the spring.
This guide helps clarify which perennials should be trimmed and which should be left standing, offering advice for fall garden maintenance.
Perennials to Cut Back in the Fall
Phlox
Phlox may bloom from the end of spring to summer, but as the weather cools, it tends to decline. Trimming them in late fall is a good idea because they are prone to powdery mildew, especially in wet conditions. Even types touted as mildew-resistant can still be affected during cool, damp falls.
Tip: Discard any infected leaves and disinfect pruners before moving on to other plants.
Bee Balm (Monarda)
Bee balm, also known as Monarda, shares a similar susceptibility to powdery mildew as phlox. Trimming these plants in the fall and removing any leftover debris helps keep this disease at bay for the next growing season.
Note: Dispose of any mildew-infected foliage and clean your trimmers before using them on other plants.
Daylilies (Hemerocallis)
Daylilies grow in dense clusters of grass-like leaves that brown and sag in winter. While cutting them back in the fall isn’t essential for the plant’s health, many gardeners prefer the tidier look through winter. It also reduces cleanup chores in the spring.
Yarrow (Achillea)
Yarrow foliage can look quite unattractive once winter arrives. Trimming back the old foliage in the fall keeps your garden tidy. Importantly, leave the new basal leaves that appear late in the season to help shield the plant’s crown during the cold months.
Advice: You can either enjoy fresh flowers indoors or leave old flower stalks standing for winter interest.
Salvia
Salvia may shine in summer but tends to flop and turn brown in winter. Some gardeners opt to leave it standing until spring, whereas others trim it back for a neater appearance.
If trimming, cut it back to the new basal growth to protect the crown over winter.
Spike Speedwell (Veronica)
Spike Speedwell, or Veronica, looks great through the growing season but fades quickly after the first frost. Cutting back to the basal foliage in late fall not only tidies up its appearance but also prepares it for regrowth in spring.
Astilbe
Astilbe’s fern-like leaves stay green until frost, after which they yellow and brown. While the foliage becomes less attractive, the spent flowers maintain their unique texture. Trimming the foliage keeps the garden neat, though leaving the spent flowers can add winter interest.
Tip: If the old blooms aren’t appealing in the garden, consider drying them for indoor arrangements.
Columbine (Aquilegia)
Columbine, or Aquilegia, is loved for its vibrant spring blooms. Clearing out old leaves and stems in late fall helps prevent diseases and pests from overwintering and gives the plant a fresh start in the spring.
Hosta
Keeping hosta foliage through winter can protect the crown, but it’s a good idea to cut it back in late fall to deter slugs, which often lay eggs in dead foliage. For those troubled by slug infestations, trimming hosta leaves after the first frost can be especially beneficial.
Suggestion: If uncertain, trim the leaves partially, leaving about 4-6 inches above ground.
Catmint (Nepeta)
Catmint, known for its aromatic leaves, retains its fresh look until frost, after which it turns yellow and brown. Some gardeners prefer cutting it back for a clean appearance. If you choose to do so, leave 4-6 inches of stem above ground to protect the crown during winter.
Perennials Not To Cut Back In Fall
Coneflowers (Echinacea)
Coneflowers, also known as Echinacea, are vibrant perennials that add color throughout the summer to the fall. Even after the flowers fade, the seed heads remain, providing food for birds like goldfinches and cardinals. For a lively winter garden, leave these standing. Their structure offers visual interest and wildlife benefits.
Coral Bells (Heuchera)
Coral Bells, or Heuchera, showcase their colorful leaves from spring to fall, lasting even into winter in warmer areas. It’s best not to cut them back in late fall because their leaves help protect the plant’s crown during the colder months. Simply tidy them up in the spring to enjoy another year of vivid foliage.
Black-Eyed Susan (Rudbeckia)
Black-Eyed Susans, or Rudbeckia, are similar to coneflowers with their prominent seed heads that attract birds in fall and winter. Leaving the seed heads can add visual interest and excitement to a winter garden. Alternatively, these can be cut back if a tidier garden appearance is preferred. The dried seed heads can also be used in flower arrangements for a unique winter display.
Red Hot Poker (Kniphofia)
Red Hot Poker, or Kniphofia, thrives in hot climates but can struggle with cold temperatures. To help the plant weather winter, it’s recommended to leave the foliage standing. This provides protection for the crown, while flower stalks can be removed. Clean it up in the spring for a healthy start to the growing season.
Ornamental Grasses
Ornamental grasses add height, movement, and structure to the garden all year round. Even in winter, these grasses turn golden and maintain their form, adding beauty to the landscape. Dried grasses with snow or frost create a stunning scene, and they can also be brought indoors for decoration. Trim them back in the spring as new growth starts.
Ferns
Ferns are loved for their delicate fronds that bring texture and shades of green to the garden. While they may lose color in winter, they should be left alone as the fronds protect the crown. In spring, new fiddleheads appear, and the old fronds can be pruned then.
False Indigo (Baptisia)
False Indigo, or Baptisia, continues to animate the garden even in winter. The once blooming flowers turn into black pods that produce a rustling sound in the wind. These pods add texture and a sense of movement, making the winter garden more dynamic.
Milkweed (Asclepias)
Milkweed, or Asclepias, is essential for pollinators. Its foliage supports Monarch caterpillars in spring while the flowers feed various birds and insects. By leaving the plants standing through fall and winter, important shelter is provided for pollinators nesting in hollow stems, ensuring they thrive come spring.
Cranesbill (Geranium)
Cranesbill, or Geranium, stands out as a hard-working perennial even in the colder months. In mild climates, it remains semi-evergreen, providing greenery in winter. It’s best to wait until spring to trim them back, enjoying their foliage throughout winter.
Stonecrop (Sedum)
Stonecrop, or Sedum, may resemble indoor succulents but they are quite hardy through winter. The fading foliage and flowers offer winter interest and food for wildlife.
Their structure, often covered in snow, adds color and a unique look to the winter garden.
Summary
When it comes to cutting back perennials in the fall, consider your garden’s needs. Some plants benefit from pruning to prevent disease, while others provide winter interest and help wildlife if left standing.
A balanced approach, where you selectively prune some and leave others, can be ideal. Tailor your strategy to your specific plants and garden goals.