Bee balm is a tough perennial, and in a garden bed it gets through winter without being wrapped or dug up. For most gardeners the real winter decision is what to do with the dying stems, not how to keep the plant warm.1The Spruce. How to Grow and Care for Bee Balm That choice depends on how the plant looked over the summer, because the same fall cutback that helps a mildewed plant can strip shelter from wildlife on a healthy one.
Why Bee Balm Survives Winter on Its Own
Bee balm grows well in USDA hardiness zones 3 through 9.2Gardenia. Monarda (Bee Balm) Plants in the ground need no special overwintering.3The Spruce. How to Grow and Care for Bee Balm Look up your zone by zip code on the USDA map.
The tops die back, but the buds for next year’s shoots sit in the crown, the clump at soil level, and in underground stems.4My Earth Garden. Bee Balm Perennial Guide: Care, Zones & Growth Tips Buds and stored food below ground are shielded from the hardest freezes.5Functional Ecology. Winter belowground: Changing winters and the perennating organs of herbaceous plants Fallen leaves and snow on top add more insulation.6Functional Ecology. Winter belowground: Changing winters and the perennating organs of herbaceous plants In winters with little snow, frost reaches deeper into the soil, which is harder on plants.7Functional Ecology. Winter belowground: Changing winters and the perennating organs of herbaceous plants
Blackened or collapsed stems after frost are normal, not damage. Before the tops die, the plant pulls stored energy down into its crown and underground stems to fuel spring regrowth.
A dormant plant looks dead. Brown, dry stems and no leaves are normal, and the roots and crown are alive underneath. Don’t dig it up to check; wait for spring shoots.
When winter does take a plant, the usual cause is soggy soil or heaving, not low air temperature, so a plant in a well-drained bed rarely needs worrying about. If one fails to return in a zone where it should be hardy, a wet spot or a young, poorly rooted plant is a likelier culprit than the cold.
Cutting Back Healthy Bee Balm in Fall
Wait until leaves fall in autumn or the first hard frost, which usually comes between mid October and December.8Savvy Gardening. When to Cut Back Bee Balm: 4 Options for Healthy Plants9Plant Addicts. Bee Balm Winter Care | Plant Addicts Cutting earlier removes leaves the plant is still using to store energy for spring.
If the plant had no mildew, you can leave it standing so birds can eat from the seed heads.10Savvy Gardening. When to Cut Back Bee Balm: 4 Options for Healthy Plants Or cut stems back to 8 to 10 inches.11Savvy Gardening. When to Cut Back Bee Balm: 4 Options for Healthy Plants Stem stubs give insects winter cover.12Savvy Gardening. When to Cut Back Bee Balm: 4 Options for Healthy Plants Tiny yellow-faced bees nest inside the hollow centers of bee balm stems.13Xerces Society for Invertebrate Conservation. Natural Nesting & Overwintering Habitat for Pollinators & Other Beneficial Insects In spring, clip any remaining stems to the ground to make room for new growth.14Savvy Gardening. When to Cut Back Bee Balm: 4 Options for Healthy Plants
If you trim, use clean, sharp pruners and cut just above the height you chose, so the stubs stay hollow and upright. Healthy cut tops can go in a corner or brush pile.
Some small native bees tunnel into the soft pith or hollow centers of stems to lay eggs, so an upright stub can serve as a nursery. Stems cut at an angle or laid on the ground are less useful, because the bees need an upright tube with an open end. The young bees stay inside through winter and emerge later, which is why spring cleanup is better delayed than rushed. Tidying everything to the ground removes bird food and bee nesting sites, and standing stems also catch snow, which adds insulation.
What to Do If Your Bee Balm Had Powdery Mildew
Powdery mildew is a fungus that coats leaves in a white, dusty film. Its spores survive winter on infected plant debris.15Yard and Garden, Iowa State University Extension and Outreach. Growing Bee Balm in the Home Garden They can overwinter on both live and dead plant material,16Homes and Gardens. Discover when to cut back bee balm during the season for strong and healthy plants so removing that debris removes the source of next year’s infection.17Yard and Garden, Iowa State University Extension and Outreach. Growing Bee Balm in the Home Garden
Cut mildewed plants right to the ground in fall.18Savvy Gardening. When to Cut Back Bee Balm: 4 Options for Healthy Plants19Homes and Gardens. Discover when to cut back bee balm during the season for strong and healthy plants Then rake up and remove fallen leaves and debris around the plant.20Savvy Gardening. When to Cut Back Bee Balm: 4 Options for Healthy Plants Never compost diseased foliage; bin it.21Savvy Gardening. When to Cut Back Bee Balm: 4 Options for Healthy Plants22Homes and Gardens. Discover when to cut back bee balm during the season for strong and healthy plants
Most backyard piles don’t get hot enough throughout to kill the spores. They can survive and come back in finished compost spread on your beds. Bag diseased material for the trash, or for yard-waste pickup where it’s allowed.
A mildewed plant shows a white to gray dusty coating on leaves and sometimes stems, and the leaves may curl, yellow, or drop early. If you saw that coating at any point in summer, treat the plant as a mildew plant in fall, even if the leaves look cleaner by autumn. Dry brown leaves at season’s end aren’t by themselves a sign of mildew, so think back to how the plant looked in midsummer.
Leave no stubs, since spores can sit on them through winter. Clean your pruners so you don’t carry spores to other plants.
Next season, water at the soil, not over the leaves, and thin crowded clumps so air moves through. Watering can also splash spores from soil onto plants, so a mulch layer helps block that splash.23Epic Gardening. How to Prevent and Treat Powdery Mildew on Bee Balm Mildew-resistant varieties are worth considering.
Mulching and Drainage for Winter
After the first hard frost, spread about a one-inch layer of mulch around the roots.24Plant Addicts. Bee Balm Winter Care | Plant Addicts Don’t mulch earlier, because it stops seeds from dropping to the soil.25Plant Addicts. Bee Balm Winter Care | Plant Addicts And don’t keep a layer of compost over plant crowns all winter, since some plants develop crown rot and die.26University of Idaho Extension. Short-Season, High-Altitude Gardening: Herbaceous ornamentals: annuals, perennials, and ornamental grasses
A hard frost is a night cold enough to blacken tender plants, so a light touch of frost that only dusts the lawn isn’t the signal. Waiting lets the plant finish dropping seed and settle into dormancy.
Shredded leaves, straw, or fine bark work well. Pull the mulch a couple of inches back from the crown. Thicker isn’t better; an inch is enough. Pull it back in spring as shoots appear.
The real winter threat is water. Water collecting in or around beds can kill overwintering plants through flooding or frost heaving.27University of Idaho Extension. Short-Season, High-Altitude Gardening: Herbaceous ornamentals: annuals, perennials, and ornamental grasses Frost heaving is soil freezing and thawing until it pushes roots up out of the ground.
After freeze-thaw swings, look for crowns sitting higher than the surrounding soil and press them gently back down. If a bed always floods, move the plant to higher ground in spring or fall.
Overwintering Bee Balm in Pots
Container roots aren’t as well insulated as roots in the ground, so in extreme cold they may need help.28The Spruce. How to Grow and Care for Bee Balm A pot is exposed to cold air on every side, so its soil can freeze solid, whereas soil in the ground is buffered by the earth around and below it. Move them to a covered outdoor greenhouse or give them winter cover until spring warms.29The Spruce. How to Grow and Care for Bee Balm
An unheated garage or shed keeps pots cold but out of the worst freezes. Grouping pots against a house wall and wrapping them helps, and so does burying a pot in a garden bed so the soil insulates it. Avoid a heated room, which can break dormancy.
Dormant plants need little water. Check monthly and water lightly if the soil is bone dry. Never let a pot sit in a saucer of water, which causes rot.
Pot material matters too. Thin plastic and terracotta lose heat fast, and terracotta can crack in freezes. Larger pots hold more soil and stay warmer. If the pot sits on bare concrete, lifting it onto feet or boards keeps cold from creeping up from below.
Spring Wake-Up and Dividing Bee Balm
As temperatures warm, new shoots come up from the crown and underground stems.30My Earth Garden. Bee Balm Perennial Guide: Care, Zones & Growth Tips Changing snow cover can make growth start earlier or later than usual.31Functional Ecology. Winter belowground: Changing winters and the perennating organs of herbaceous plants Once they appear, clip any old stems you left standing down to the ground.32Savvy Gardening. When to Cut Back Bee Balm: 4 Options for Healthy Plants
Bee balm wakes up after many other perennials, so bare soil in early spring is not a sign of failure. Rake mulch back so the soil warms, and remove any leftover leaves from a mildew year. If you can, leave hollow stem stubs until bees have emerged.
If nothing shows by late spring, scratch the crown gently. Firm, pale tissue suggests it’s alive. A mushy, dark crown suggests rot from wet winter soil, which points to a drainage problem.
Bee balm can be divided in early spring or late summer.33Plant Addicts. Propagating Bee Balm A clump left alone for several years tends to die out in the middle, and crowded stems favor mildew, so divide every few years. In warmer zones, dividing from late summer to late fall, when it’s cooler, works better.34Plant Addicts. Propagating Bee Balm Northern gardeners should favor spring so divisions have the whole season to root before winter.
Dig around the clump and lift it with a spade. Cut it into pieces, each with roots and several shoots, and discard the woody, dead center. Replant at the same depth and water well. The new pieces can go elsewhere in your garden or to other gardeners.