Is It Bad to Skip Cutting Back Your Perennials Before Winter? Here’s What to Know

Pruning perennials at the right time encourages plants to leaf out, grow bushier, develop sturdier stems, and potentially produce more flowers. But when is the right time to prune perennials, and will plants suffer if you don’t cut them back before winter?

Here’s a look at the pros and cons of pruning perennials in fall vs. spring and a list of the plants that you should and shouldn’t prune before winter.

Potential Problems If You Don’t Cut Perennials Back

For the most part, less is more when it comes to pruning. Most perennials will be just fine if you don’t cut them back before winter. When the weather turns chilly, plants naturally enter a state of dormancy and draw energy down from their leaves and stems into their roots, which helps plants survive the cold without damage. When the weather warms again, plants simply send energy back up to their leaves, or they produce entirely fresh growth in spring. This happens regardless of whether you prune them or not.

But while most perennials don’t need to be cut back in fall, there are a few instances when failure to prune them can actually make plant problems worse, such as

• Pests and diseases. If your plants were plagued by pests or diseases during the growing season, leaving diseased plant debris in your garden allows problems to overwinter and reinfect your plants in spring. In this instance, it’s best to prune and rake up all diseased plant material in the fall and to destroy all that old debris by throwing it in the trash or burning it in your firepit. Do not compost diseased plants, as it perpetuates pests and disease issues.
• Self-sowing. Some plants readily self-sow and may aggressively spread into areas where you don’t want them. Pruning, or at least deadheading, these plants before winter makes them easier to control and ensures you won’t need to weed out tons of seedlings in spring.
• Broken branches on woody perennials. Shrubs and other plants with woody stems or branches that are broken should also be pruned before winter to remove any damaged parts. Leaving broken branches and stems in place potentially makes branch damage worse, allows bark to tear further, and leaves plants more exposed to diseases and winter winds.
• Appearance. Some plants look a bit scruffy in winter, and they may not appeal to gardeners who prefer a tidy garden look. Pruning these plants in autumn makes gardens look more refined in winter and reduces the number of gardening chores in spring.

Benefits of Leaving Perennials Standing

Although pruning perennials in autumn reduces pest and disease issues and provides a few other benefits to plants, many gardeners prefer to wait until spring to do the majority of their pruning. This is partly due to personal preference, but leaving plants standing through winter also helps certain plants grow better and even provides perks to local wildlife. If you’re on the fence about when to prune perennials, here are some reasons why you may want to wait until spring to pick up your pruners.

• Better root insulation. Leaving stems and leaves intact through winter provides extra insulation to plant roots and crowns and protects plants from cold damage. This is especially true for plants that are marginally hardy in your area, as well as common perennials like woodland phlox, lamb’s ear, and hardy geraniums.
• Winter interest. Unpruned plants may look a little wild in early winter, but they can look downright magical when they’re covered with a light dusting of frost and snow. Plants like goldenrod, hydrangeas, and sedums keep their dried flowerheads all winter long and look particularly pretty when the snow starts falling!
• Attract wild birds. Leaving dried flowers in place through winter also attracts seed-eating birds like finches that feast on protein-packed flower seeds. Perennials like black-eyed Susan, coneflowers, and bee balm are well-known for attracting birds in winter.
• Protect local pollinators. Many solitary bees, moths, and other pollinators overwinter in old leaf litter or in the hollow stems of perennial plants. Waiting until spring to do your pruning and garden cleanup ensures that these beneficial insects have a place to shelter during the colder months.
• Free plants. Many plants will also self-sow if you don’t deadhead their old flowers, which provides you with free plants and naturally expands patches of perennials. This includes plants like bee balm, black-eyed Susan, columbine, foxglove, and lupine.

Perennials to Prune in Fall vs. Spring

Some plants have specific pruning needs and prefer to be pruned at a specific time of the year, so it’s important to do a bit of research on the perennials in your garden. However, these basic guidelines help you determine which plants to prune in autumn or spring.

Plants to Prune in Autumn

• All plants that were affected by pests and diseases, as well as plants that are prone to mildew problems, like peonies, bee balm, and phlox. Pruning hostas in the fall is also wise, as they often harbor slug eggs.
• Woody plants with broken or damaged stems and branches.
• Any plants that you don’t want to self-sow.
• Plants with grass-like leaves, such as irises, lilies, liatris, and daylilies. They often look tidier with autumn pruning, but trimming them in the fall is optional.

Plants to Prune in Spring

• Plants with cold-sensitive surface roots and crowns, like lady’s mantle, Russian sage, and coral bells.
• Plants that provide winter interest, including sedums, goldenrod, blue false indigo, and ornamental grasses.
• Flowers that produce lots of seeds, like coneflowers, that attract wild birds
• Plants that bloom on old wood, like lilacs, azaleas, and big leaf hydrangeas. They should be pruned in spring to avoid removing their flower buds.
• Plants with hollow stems, like purple flowering raspberry and Joe Pye weed. They provide shelter for solitary bees and should also be left as-is in winter to protect slumbering pollinators.