Should I cut back perennials in fall or spring?

Either can be right. Penn State Extension says cut back diseased plants, hostas and plants that add nothing to the winter garden in fall, and leave grasses, seed heads, marginally hardy perennials and low evergreen perennials until spring. Oregon State University Extension says waiting until spring is fine and gives native pollinators winter habitat.

Which perennials should I not cut back in fall?

Penn State Extension says leave ornamental grasses, plants with seed heads birds eat such as purple coneflower and black-eyed Susan, marginally hardy perennials such as garden mums and red-hot poker, and low evergreen perennials such as heucheras and hellebores.

How far down should I cut perennials?

Penn State Extension says leave about two inches above the soil to mark where the plant is. In central Oregon, Oregon State University Extension cuts to 6 to 8 inches, so the stems hold snow that insulates the plant.

Should I cut back ornamental grasses in fall?

Penn State Extension says no: leave them standing for winter, then cut them back in spring before the new shoots appear.

Why cut back hostas in fall?

Penn State Extension says cut hostas back and remove all their leaves as soon as frost takes them, because dead hosta leaves harbor slug eggs.

Should I mulch perennials for winter?

Oregon State University Extension says most perennials get 2 to 5 inches of mulch, applied after the ground has frozen lightly so it keeps the soil frozen. Some do better with none, and some tender ones want 5 inches or more.

Guides

When to Cut Back Perennials in Fall, and What to Leave

Penn State Extension’s answer to “should I cut my perennials down in fall?” is “it depends”. Diseased plants and hostas come down as soon as frost takes them. Grasses, seed heads, tender perennials and low evergreens stay up for winter. Everything else can go either way, and leaving it is often the better choice.

Published October 23, 2026 · Cite this page

Cut or leave: plant by plant

Every plant here is one Penn State Extension names, in the group it puts it in.

Plants	In fall	Why
Ornamental grasses: switch grass, zebra grass, feather reed grass	Leave	Winter interest; cut back in spring before new shoots appear
Siberian iris, blue false indigo	Leave	Black seedpods that stand out against snow
Sedum ‘Autumn Joy’, Joe Pye weed	Leave	Seed heads that hold all winter
Purple coneflower, black-eyed Susan, oxeye sunflower	Leave	Seed for birds; goldfinches feed on coneflower
Garden mums, anise hyssop, red-hot poker, Montauk daisy	Leave	Marginally hardy: the tops catch leaves and snow that insulate them
Hardy geraniums, heucheras, hellebores, dianthus, moss phlox	Leave	Low evergreen or semi-evergreen; tidy in spring
Bee balm, garden phlox with powdery mildew	Cut	Reduce next year’s infection; destroy, do not compost
Hostas	Cut as soon as frost takes them	Dead leaves harbor slug eggs; clear them from the ground
Peonies, daylilies, brunnera, speedwell	Cut	Browning foliage and bare stalks that add nothing in winter
Yarrow, Shasta daisy, globe thistle	Cut the stalks only	They grow new basal leaves late in the season; leave those

Penn State also notes that beneficial insects overwinter in or near native plants as pupae, caterpillars or eggs, and that the viceroy butterfly spends winter rolled in a leaf on the ground — a reason not to rake debris from around perennials.

When to cut

Penn State: Unless the plant is diseased or infected, wait until several hard frosts have killed back the tops. The roots reclaim energy from the dying plant, and leaving tops on over winter is fine for many perennials and may be better. For when your first freeze usually comes, enter your ZIP code below, or see what can I still plant, which counts down to it.

How the advice changes by region

Where	When to cut	How low	What to leave
Pennsylvania (Penn State)	After several hard frosts, unless diseased	About 2 inches, to mark the spot	Grasses, seed heads, marginal and evergreen perennials
Central Oregon (Oregon State)	Late fall or early winter as plants die back and go dormant, or wait until spring	6 to 8 inches, so the stems hold insulating snow	Stems and plant material, for native pollinators and winter texture, if you wait
Solano County, California (UC Master Gardeners)	Seed heads can come off in early spring	Not given	Seed heads and pods for birds, hollow stems for solitary native bees, fallen leaves as mulch

Step by step

Cut the diseased plants and hostas first. Penn State says destroy diseased stems and leaves rather than compost them; UC Master Gardeners in Solano County say the same of leaves and fruit from diseased plants.
Wait on the rest. Several hard frosts, Penn State says.
Leave a marker. Penn State says leave about 2 inches of stem, especially on late risers such as butterfly weed, rose mallow and balloon flower, so you do not dig into them in spring.
Use bypass pruners. Penn State says they cut cleanly; hedge clippers or a power trimmer work for a large planting.
Mulch after the ground freezes. Oregon State says 2 to 5 inches for most perennials, applied after the ground has frozen lightly, so the mulch keeps it frozen through freeze–thaw cycles.
Water in dry, snowless spells. Oregon State says water when the top of the ground has thawed and can take water, every four to six weeks during those periods.

Mulch or no mulch

Oregon State’s central Oregon lists, in part:

Group	Examples Oregon State names
Prefer no added mulch (wet soil, root rot)	Aster, black-eyed Susan, coreopsis, daylily, dianthus, iris, lamb’s ear, penstemon, purple coneflower, Russian sage, salvia, sedum, yarrow, most ornamental grasses
Prefer extra mulch, 5 inches or more	Ajuga, bergenia, chrysanthemum, English daisy, lavender, pincushion flower, plumbago, wallflower, bulbs

Your ZIP code

Your ZIP, your answer

Enter your ZIP code to see your USDA zone and the freeze dates of the NOAA station nearest you.

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Full details for any ZIP code: ZIP code zone finder.

Common mistakes

Cutting everything down at the first frost. Penn State says wait for several hard frosts unless a plant is diseased.
Composting mildewed phlox and bee balm. Penn State says destroy them.
Leaving hosta leaves on the ground. They harbor slug eggs (Penn State).
Cutting garden mums to the ground. Penn State says their tops help them survive winter.
Cutting late risers flush with the soil. Leave a 2-inch marker (Penn State).
Mulching before the ground freezes. Oregon State says mulch after a light freeze, to keep the ground frozen.
Raking every leaf. UC Master Gardeners in Solano County say leaves are a natural mulch and winter habitat, except leaves from diseased plants.

In the South

We found no source from the Southeast or Texas on cutting back perennials, so advice for the South here is limited. The Solano County source writes for a mild-winter California valley. Where winters are mild, ask your county extension office.

ZIP code zone finder — your exact USDA zone and nearest NOAA station
What survives my winter? — perennial edibles checked against your zone
Perennial herbs and flowers by zone: Lavender, Rosemary, Mint, Thyme, Oregano, Sage, Chives, Tarragon, Peony, Hosta, Clematis, Iris, Daylily, Coneflower, Black-eyed Susan, Salvia, Garden phlox, Astilbe, Tulip, Daffodil, Crocus and Hyacinth.
Plant guides by zone — shrubs and trees, herbs, flowers and holiday plants
How to Protect Plants from Frost: Covers, Timing, Temps
How to Overwinter Dahlias, Cannas and Tender Bulbs by Zone
How to Protect Shrubs from Winter Damage

Questions

Should I cut back perennials in fall or spring?: Either can be right. Penn State Extension says cut back diseased plants, hostas and plants that add nothing to the winter garden in fall, and leave grasses, seed heads, marginally hardy perennials and low evergreen perennials until spring. Oregon State University Extension says waiting until spring is fine and gives native pollinators winter habitat.
Which perennials should I not cut back in fall?: Penn State Extension says leave ornamental grasses, plants with seed heads birds eat such as purple coneflower and black-eyed Susan, marginally hardy perennials such as garden mums and red-hot poker, and low evergreen perennials such as heucheras and hellebores.
How far down should I cut perennials?: Penn State Extension says leave about two inches above the soil to mark where the plant is. In central Oregon, Oregon State University Extension cuts to 6 to 8 inches, so the stems hold snow that insulates the plant.
Should I cut back ornamental grasses in fall?: Penn State Extension says no: leave them standing for winter, then cut them back in spring before the new shoots appear.
Why cut back hostas in fall?: Penn State Extension says cut hostas back and remove all their leaves as soon as frost takes them, because dead hosta leaves harbor slug eggs.
Should I mulch perennials for winter?: Oregon State University Extension says most perennials get 2 to 5 inches of mulch, applied after the ground has frozen lightly so it keeps the soil frozen. Some do better with none, and some tender ones want 5 inches or more.

Sources

Every plant, timing and height on this page is quoted from the extension publications below, each written for its own area. Zones beside each source are the USDA Plant Hardiness Zone Map, 2023.

Penn State Extension, Cutting Down Perennials in the Fall , by Nancy Knauss and Pamela T. Hubbard (Updated September 9, 2026). Written for: Pennsylvania (USDA zones 5b–8a).
Oregon State University Extension Service, Winter care of perennials in central Oregon , by Amy Jo Detweiler (Published January 2009, reviewed 2024). Written for: Central Oregon.
UC Master Gardeners, Under the Solano Sun (University of California), Falling Behind? Maybe Not! (October 8, 2024). Written for: Solano County, California (USDA zone 9b).

Nothing here replaces your own state's cooperative extension service, which knows your county. Where this site's numbers come from.

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