When fall arrives in Wisconsin, it’s tempting to grab the pruners and clean up every perennial, ornamental grass, and shrub before winter.
But a completely “clean” landscape isn’t always a healthier landscape.
Some plants benefit from being cut back in fall, while others are better left standing through winter. Leaving the right plants alone can provide winter interest, protect plant crowns, provide habitat for beneficial insects, and offer seeds and shelter for birds.
Here’s how to decide what should stay and what can go.
What You’ll Need
For a typical fall garden cleanup, you don’t need much:
- Sharp hand pruners
- Loppers for thicker stems
- Garden gloves
- Rake
- Tarp or yard-waste container
- Disinfectant for pruning tools
Before moving between plants—especially if you’ve been cutting diseased material—clean your pruning tools to reduce the chance of spreading disease.
Cut Back Diseased Plant Material
This should be one of your fall priorities.
If a perennial has experienced significant fungal disease, leaf spots, mildew, or other disease problems during the growing season, removing affected foliage can help reduce infected material left in the garden.
Cut diseased perennial material near the ground and remove it from the bed.
Don’t use obviously diseased material as home compost unless you know your compost pile reaches temperatures capable of destroying the pathogen.
Homeowner Tip
If you’re unsure whether you’re looking at normal fall decline or a disease problem, take a few clear pictures before removing the plant material. They can be useful later if you need help identifying the problem.
Cut Back Collapsed or Messy Perennials
Some perennials simply don’t offer much value once they’ve been hit by frost.
Plants that become soft, flattened, slimy, or badly broken can generally be cleaned up once they’ve gone dormant.
Remove the dead top growth while leaving the crown and root system undisturbed.
Avoid pulling stems aggressively from the ground. Cutting them is safer because pulling can disturb the crown or roots.
Leave Healthy Perennials With Seed Heads
Not everything needs to disappear.
Coneflowers, black-eyed Susans and many other flowering perennials develop seed heads that can provide food for birds during fall and winter.
Their stems can also provide habitat for insects.
If the plants are healthy and aren’t creating a problem, consider leaving them until spring.
Your landscape may look a little less manicured, but that’s not necessarily a bad thing.
Leave Ornamental Grasses Standing
In most situations, we recommend leaving ornamental grasses standing through winter.
Their foliage provides:
- Winter texture and movement
- Habitat and shelter
- Protection around the plant crown
- Visual interest when much of the landscape is dormant
Snow and frost on ornamental grasses can also look great during a Wisconsin winter.
Wait until late winter or early spring to cut them back before new growth begins.
Be Careful With Shrubs
Fall cleanup doesn’t mean every shrub needs pruning.
This is an area where homeowners can unintentionally remove next year’s flowers.
Some flowering shrubs develop their flower buds on old wood, meaning the buds for next year’s flowers are already present on stems produced this year.
Heavy fall pruning can remove those buds.
Other shrubs flower on new growth and tolerate different pruning schedules.
If you aren’t sure what shrub you have or when it should be pruned, identification should come before pruning.
A Simple Rule
Don’t prune a shrub simply because it’s fall.
Know what the plant is and why you’re pruning it first.
Dead, damaged, or clearly broken material is a different situation, but routine shaping can usually wait until the appropriate pruning window for that particular species.
Don’t Automatically Cut Hydrangeas Down
Hydrangeas are a common source of pruning mistakes because different types have different requirements.
Some bloom primarily on new wood, while others bloom on old wood.
Cutting the wrong hydrangea back at the wrong time can mean removing next year’s flowers.
If you don’t know which type you have, leaving it alone is usually better than guessing.
What About Hostas?
Once hosta foliage has been killed by frost and begins collapsing, it can be removed.
Cut the foliage near the base rather than pulling aggressively at the plant.
Removing the dead foliage can also reduce hiding places for slugs and make spring cleanup easier.
Don’t Forget the Leaves
Leaves in landscape beds aren’t automatically a problem.
A light layer of shredded leaves can break down and return organic matter to the soil. Leaves can also provide habitat for beneficial insects.
Problems occur when heavy layers of wet, matted leaves cover low-growing plants or lawn areas.
Instead of thinking that every leaf needs to disappear, think about where the leaves are and how thick the layer is.
Heavy accumulations should be removed or redistributed. A lighter layer in appropriate garden areas can often remain.
Don’t Forget to Water
One of the most commonly overlooked fall landscape tasks has nothing to do with pruning.
It’s watering.
Trees, shrubs, and perennials can still need moisture after temperatures cool, particularly newly planted material.
If fall is dry, continue watering until the ground begins to freeze. Newly planted trees and shrubs deserve particular attention because their root systems haven’t yet expanded into the surrounding soil.
A good soaking less frequently is generally more useful than repeatedly wetting only the surface.
A Simple Fall Cleanup Checklist
- Remove diseased plant material.
- Remove collapsed or damaged perennial foliage.
- Leave healthy seed heads when practical.
- Leave ornamental grasses standing.
- Identify shrubs before pruning them.
- Avoid unnecessary fall shrub pruning.
- Remove heavy, matted leaf accumulations.
- Consider leaving some healthy leaves in appropriate garden areas.
- Continue watering trees and shrubs during dry fall weather.
- Pay extra attention to anything planted this year.
- Clean and disinfect pruning tools.
- Leave healthy habitat where it makes sense.
When Should You Call a Professional?
Most homeowners can handle basic perennial cleanup, leaf removal, and simple garden-bed maintenance themselves.
Professional help makes sense when you’re dealing with large or overgrown shrubs, trees, suspected diseases, difficult-to-identify plants, extensive landscape beds, or pruning that requires ladders, chainsaws, or powered equipment.
Tree pruning in particular shouldn’t be treated as an extension of ordinary fall garden cleanup. Larger limbs, overhead hazards, structural defects, and work near buildings or utilities require appropriate training and equipment.
A Better Fall Cleanup Isn’t Always a Cleaner One
The goal shouldn’t be to make every landscape bed completely bare before snow arrives.
A thoughtful fall cleanup removes material that could create problems while leaving healthy plants, seed heads, grasses, and habitat where they provide a benefit.
A little less cleanup this fall can sometimes mean a healthier—and more interesting—landscape all winter.
And if you’d rather spend your fall weekends doing something other than hauling leaves and cutting back garden beds, Tim Andrews Horticulturist LLC can help with seasonal landscape cleanup and maintenance.
Let us care for your green world.
1 Comment