By October, the garden can start looking a little tired.
In some areas, Summer flowers are fading, leaves are yellowing, and some perennials have already been touched by the first chilly nights of fall.
That makes it tempting to grab your pruners and start cutting everything back.
But not so fast.
Some plants benefit from being cleaned up in fall, especially if their foliage can harbor diseases or pests over winter. Others are better left standing until spring because their seedheads feed birds, their stems shelter beneficial insects, or they simply provide winter interest.
The most important thing to remember is that October is a guideline, not a deadline.
If your plants are still green and actively growing, give them more time. But once the foliage has yellowed, browned, or been damaged by frost, these are some of the plants you can start cutting back.
1. Peonies
Peonies are one perennial I like to clean up before winter.
By October, especially in colder parts of the country, peony foliage often begins turning yellow, brown, or black. Once the leaves start dying back, there is little benefit to leaving them standing.
In fact, removing the old foliage can be helpful because peonies are susceptible to fungal diseases that can survive on infected leaves and stems.
Wait until the foliage is clearly declining, then cut the stems down to about 2 to 3 inches above the soil.
Pick up the clippings and any fallen peony leaves around the plant. If the foliage showed signs of disease during the season, don’t add it to your regular compost pile.
This little bit of cleanup now can help give your peonies a cleaner start next spring.
2. Bearded Irises
Bearded iris foliage can look pretty rough by October.
The leaves may be yellowing, spotted, floppy, or damaged from months of summer weather.
Once the foliage begins dying back, you can trim it down to about 4 to 6 inches tall.
Removing old foliage also helps clean up hiding places for pests and removes leaves that may have developed fungal spots during the growing season.
However, don’t rush to cut perfectly healthy green leaves early in fall.
As long as the foliage is still green, it is helping the plant store energy in its rhizomes for next year’s flowers.
Once it starts yellowing and declining, that’s your sign that it’s time for cleanup.
3. Daylilies
Daylilies often tell you when they’re ready for a fall haircut.
By October, their long leaves may start turning yellow, brown, or mushy after a frost.
At that point, you can cut the foliage back to about 4 to 6 inches above the ground.
You can also simply pull away dead leaves if they come loose easily.
Removing that collapsing foliage makes the garden look much tidier and gets rid of wet plant material that can become messy as winter approaches.
If your daylily leaves are still mostly green, though, leave them alone for a little longer.
Those green leaves are still photosynthesizing and sending energy back into the plant.
4. Hostas
Hostas can go from beautiful to terrible-looking almost overnight after the first hard frost.
Their big green leaves collapse into a soggy pile of yellow or brown foliage.
Once that happens, it’s a good time to remove them.
Cut the foliage down near the base of the plant, leaving a few inches if necessary.
Removing dead hosta leaves can also eliminate places where slugs and other garden pests may hide or overwinter.
But don’t cut healthy hostas just because the calendar says October.
In warmer areas, hostas may remain green well into fall. Wait until frost or natural dormancy causes the leaves to yellow and collapse.
5. Garden Phlox
Garden phlox can be a good candidate for fall cleanup, especially if you battled powdery mildew during the summer.
That familiar white or gray coating on the leaves is common on phlox, and infected foliage shouldn’t be left lying around the garden.
Once your phlox has finished blooming and the foliage begins dying back, cut diseased stems down close to the ground and remove the debris.
Don’t compost foliage that was heavily affected by disease.
If your plants were healthy, you don’t necessarily have to remove every stem.
Leaving a few sturdy stems standing can provide winter habitat for insects. But if mildew was a problem, October cleanup is worthwhile.
6. Bee Balm
Bee balm is another perennial that frequently develops powdery mildew by the end of summer.
If your plants look covered in white powder, have brown leaves, or are generally declining, fall is a good time to clean them up.
Cut badly affected stems down to a few inches above the soil and remove the diseased foliage from the garden.
Healthy bee balm is a little different.
Its dried seedheads can provide food for birds, and the standing stems can provide shelter for overwintering insects.
So there’s no need to cut down a healthy patch simply because it’s October.
Think of this one as a selective cleanup. Remove unhealthy material, but consider leaving healthy stems standing until spring.
7. Asiatic and Oriental Lilies
True lilies should not be cut down immediately after they finish flowering in summer.
The leaves need time to continue making energy and storing it in the bulb for next year’s flowers.
By October, however, the foliage often begins yellowing naturally.
Once most of the leaves and stems have turned yellow or brown, you can cut the stalks down to a few inches above the ground.
The important part is waiting for that color change.
If the stems are still green, leave them alone.
Cutting green lily foliage too early can interfere with the plant’s ability to replenish the bulb for the following season.
8. Shasta Daisies
Shasta daisies can become floppy and unattractive by the end of the growing season.
After the flowers are finished and the foliage has started turning brown or has been hit by frost, you can cut the spent stems back.
You don’t necessarily need to scalp the plant right down to bare soil.
Leaving a few inches of growth can help mark where the plant is located and provide a little protection around the crown.
If parts of the plant are still green, you can also take a lighter approach and simply remove the dead flower stalks and obviously declining foliage.
The key is to let the plant begin entering dormancy before giving it a major haircut.
9. Catmint
Catmint can look pretty tired by October after flowering for much of the summer.
If the stems have become brown, floppy, or damaged by frost, you can trim the plant back and clean up the bed.
However, I wouldn’t cut healthy catmint to the ground while it is still green.
In colder climates, leaving several inches of growth above the crown can provide a little extra protection going into winter.
You can always finish the cleanup in early spring once you see new growth beginning at the base.
For October, concentrate on removing the worst-looking dead and damaged stems.
10. Lamb’s Ear
Lamb’s ear can struggle with wet, decaying foliage during cool fall weather.
Those soft, fuzzy leaves sometimes turn brown or begin rotting around the base of the plant.
October is a good time to remove damaged, diseased, or mushy leaves before winter.
Instead of shearing the entire plant to the ground, selectively remove the foliage that looks bad.
Leave healthy leaves in place.
This allows you to improve air circulation around the crown without unnecessarily removing healthy growth that may persist through much of the winter in milder climates.
But Don’t Cut Everything Back!
Once you get started with fall cleanup, it’s easy to keep going.
But some plants are actually more useful to your garden if you leave them standing through winter.
Their seedheads can become natural bird feeders, while hollow stems and dried foliage may provide shelter for beneficial insects.
Here are a few plants I would think twice about cutting down in October.
Leave Coneflowers Standing
Those dark, prickly coneflower seedheads may not look as impressive as they did in July, but birds don’t seem to mind.
Finches and other seed-eating birds may visit the dried flower heads during fall and winter.
The stems also provide structure in an otherwise empty winter garden.
Unless the plant is diseased, leave at least some of your coneflowers standing and cut them back in spring instead.
Leave Black-Eyed Susans Standing
Black-eyed Susans are another plant worth leaving alone after flowering.
Their dried seedheads can provide food for birds during the colder months.
They also add texture to the winter garden instead of leaving you with a completely bare flower bed.
You can remove any diseased foliage, but healthy plants don’t need to disappear in October.
Leave Ornamental Grasses Standing
This is one of the easiest fall garden chores to skip.
Ornamental grasses often look their best during winter.
Their tall stems and seedheads add movement to the garden, catch frost and snow, and provide valuable winter structure.
Rather than chopping them down in October, leave them standing through winter.
Cut the old growth back in late winter or early spring, shortly before fresh green shoots begin appearing from the base.
Leave Sedum Seedheads
Those dried sedum flower heads can remain attractive long after the flowers fade.
They also provide food for birds and look beautiful when covered with frost.
Unless the plant has disease problems or you simply can’t stand the appearance, there’s no rush to cut sedum down in October.
Let it stay until spring.
One Simple Rule Before You Start Cutting
Instead of asking:
“Is it October yet?”
Ask:
“Is this plant finished growing for the season?”
If the foliage is still green and healthy, it’s probably still helping the plant store energy.
If it has yellowed, browned, collapsed after frost, or developed disease, cleanup may make sense.
And if the plant has attractive seedheads that birds love, you may want to leave it alone completely.
The best fall garden doesn’t have to be perfectly clean.
A little strategic cleanup can reduce disease and remove messy foliage, while leaving the right plants standing can provide food and shelter for wildlife all winter long.
So grab your pruners in October, but don’t use them on everything you see.
