Fall planting perennials works best about six weeks before your area's average first frost, while the soil is still warm. Bare-root, dormant perennials suit fall well: they spend the cool months growing roots, not leaves. Soak the roots, plant with the crown at soil level, water well, and mulch once the ground turns cold.
Fall is a good season to plant perennials because the soil holds its summer heat while the air cools, which gives new roots time to grow before winter. That suits the way most of our plants travel. This is the customer education site of TN Nursery, a third-generation family nursery in Altamont, Tennessee, growing native trees and plants since 1959. We ship most plants bare-root and dormant, so a fall order arrives as roots and a crown, often with no green leaves at all. That is normal. A dormant plant is resting, and fall is when it can settle in with little stress. This guide is for the box on your porch, not a pot from a garden center: how to time your planting from your frost date, what to do with bare roots the day they arrive, how deep to set them, and how to carry them through their first winter so they come back strong in spring.
Fall planting perennials, step by step
- Perennials for sun, such as black-eyed Susan or purple coneflower
- A shade plant such as Christmas fern for spots under trees
- A bucket of water, a spade, and shredded leaves or bark for mulch
1. Count back six weeks from first frost
Look up your average first frost date, then count back about six weeks. That is your target for getting roots in the ground. The University of Illinois Extension advises planting six weeks ahead of the first frost, because warm soil helps new roots grow while the air cools. Later plantings can still work in mild areas, but the roots get less time to anchor before the ground freezes.
Tip: Your local cooperative extension office can give you the frost date for your area.
2. Open the box and soak the roots
Open your box the day it arrives. Dormant perennials may look like a tangle of roots with a bud or two at the top; that is how they should look. Keep the roots moist from here on. Set them in a bucket of water while you prepare the bed, and plant them the same day if you can. Roots left to dry out in wind or sun can fail to take.
Tip: Can't plant yet? Wrap the roots in damp newspaper and keep the box somewhere cool and shaded.
3. Plant with the crown at soil level
Dig a hole wide enough to spread the roots out without bending them. Loosen the soil at the bottom, fan the roots over a small mound, and set the plant so the crown, where roots meet stem, sits at soil level. Too deep and the crown can rot; too shallow and the roots dry out. Firm the soil gently around the roots to close any air pockets.
Tip: Plant on a cool, cloudy day if you can, so the roots stay moist.
4. Water in, then mulch
Water each plant slowly and deeply right after planting so the soil settles around the roots. Then water as needed whenever the soil dries, through the rest of fall. Illinois Extension advises you to stop watering after the first hard freeze. Once the ground is cold, spread a layer of mulch, such as shredded leaves or bark, around the plants, keeping it off the crown itself.
Tip: Mark each spot with a label so you don't dig into dormant plants in spring.
Natives that establish well in fall
For a sunny bed, a good place to start is the two Susans. Black-eyed Susan has golden-yellow petals around a dark brown or black cone, and brown-eyed Susan has showy yellow petals around a dark conical center. TN Nursery ships most plants bare-root and dormant, so expect them to arrive ready for the steps above. Purple coneflower makes a good partner, with pink to purple petals around a raised orange-brown cone. For the shady spots under trees, Christmas fern is one of the easier ferns to grow and suits a woodland edge. If you are planting along a walk, a fence or the front of a bed, our Border Plants collection gathers sturdy plants chosen to mark a garden's edge. Fall planting gives every one of these a head start. When spring warms the soil, the roots are already in place, and the plant can put its energy into new leaves and flowers rather than settling in.
Care and keeping: On established plants, leave the stems and seedheads of black-eyed Susans and coneflowers standing over winter rather than cutting them down, and keep mulch a few inches from each crown. Through winter, a new bare-root bed will show little or nothing above ground. That is normal for dormant perennials. Look for fresh growth as the soil warms in spring.
Frequently asked questions
Is it too late to plant perennials in October?
Not always. If your average first frost is six or more weeks away, October is fine. If it is closer, roots get less time to anchor, so plant the day your box arrives, water well, and mulch once the ground turns cold. Check your local frost date first; it varies widely from north to south.
What should you not plant in the fall?
Avoid planting so late that roots have no time to grow before the ground freezes. A perennial set out just ahead of a hard freeze has little chance to anchor, and freezing and thawing can push it out of the soil. In very cold regions, some growers skip fall planting altogether and wait for spring.
What perennials should you not cut down in the fall?
Many gardeners leave sturdy, seed-bearing perennials such as black-eyed Susan and purple coneflower standing until spring. Their stems mark where each plant sits, and the seedheads add winter texture to the bed. Ferns can also be left alone; tidy old fronds in spring once new growth appears.
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