Plants Popping Out of the Soil in the Frost? Here's Why and How to Replant Them Safely
It's unsettling to see your plants being shoved out of their garden beds in the middle of winter. Learn about frost heave and how to fix your perennials safely.
Walk past your garden beds on a winter morning and you might notice plants that were snug in the soil last fall are now sitting an inch or two higher, their crowns exposed, roots visible. This isn't your imagination—it's frost heave, and it can kill perennials if you don't fix it.
Frost heave happens when repeated freezing and thawing cycles push plants right out of the ground, exposing roots to cold and wind—catch it early by checking for lifted crowns and mounded mulch, then gently backfill with soil and add protective mulch to save your perennials.
Frost heave shows up most often after those back-and-forth temperature swings that create the perfect conditions. Preventing frost heave in your garden starts with understanding what causes it.
Why Are My Plants Popping Out of the Ground?
Water in soil freezes and expands, which pushes everything upward—soil, plants, roots. Then temps warm up, things thaw and settle. The next cold snap freezes another layer, creating what's basically an ice lens under your plants. This happens over and over, uprooting plants a little higher each time.
The real damage happens when roots break or get fully exposed. Broken roots can't take up water or nutrients. Exposed roots dry out in the winter wind and freeze solid. The plant's crown sits there naked instead of protected by soil. Most perennials won't survive this for long.
Spot Frost Heave Early
Check your beds when temperatures fluctuate. Look for plants that seem taller than they should be, or mulch that's mounded up instead of flat. Pull back mulch and look at the crown—if you can see the top of the root system or there's a gap between crown and soil, that's frost heave.
Shallow-rooted perennials show it first. Coral bells, strawberries, mums, blanket flowers—they have roots that don't go deep, so they lift easily. Anything planted late fall is vulnerable too since roots haven't had time to anchor. Check low spots in your garden, since these hold more moisture and get hit harder by freeze-thaw cycles.
How to Replant Heaved Perennials Safely
Don't try jamming the plant back down into frozen soil. That compresses and damages roots. Instead, wait for a day when soil isn't frozen solid. Remove mulch carefully from around the plant. Add loose soil around the exposed roots and crown—just gently pat it enough to fill gaps and cover roots.
If the plant is leaning or loose, you might need to support it temporarily. These bamboo stakes from Amazon work well. Don't pull the plant tight against the stake; give it some slack. The goal is stability, not rigidity.
Dealing With Severe Cases
Sometimes plants are too far gone to fix midwinter. If roots are completely out of the ground and dried out, or the plant's flopping sideways, cover exposed roots with soil and mark the spot for spring. Pile on three to four inches (8-10cm) of mulch—heavier wood chips work better than straw.
These plants probably won't make it through winter, but at least the roots stay protected until you can dig them up in spring and replant at the right depth.
Mulching to Prevent Further Damage
Once you've fixed heaved plants, add a few inches of mulch to prevent it happening again. This recycled hardwood mulch from the Home Depot, shredded leaves, or pine needles all work for insulating soil and preventing heave.
Don't pile mulch directly on plant crowns though. Leave an inch or two of space around stems. Mulch sitting against crowns traps moisture and causes rot. The weight of mulch also helps keep from heaving as much.
Why This Keeps Happening
Clay and loam soils hold tons of moisture, which means more water available to freeze and expand. Sandy soil drains better and heaves less. If your beds keep having heave problems, working compost into soil improves drainage and reduces the issue.
Late planting causes heave too. Perennials need at least six weeks before first frost to establish roots. Plant in late September and roots don't have time to anchor before freeze-thaw cycles start.
How to Fix Frost Heave Long-Term
Spring planting gives perennials a full growing season to develop deep root systems that resist heaving. If you plant in fall, stick to early fall—late August or early September. Any later and you’ll need to baby plants through winter with heavy mulch and checks.
Improve drainage in problem areas. Raised beds heave less than low-lying spots. Working compost into clay soil helps water drain instead of sitting there ready to freeze. Choose deeper-rooted perennials for heave-prone areas. Peonies, daylilies, and hostas establish stronger root systems.
Check your beds regularly through winter. Catching heave early means you can fix it before roots die. A quick walk through the garden every few weeks during freeze-thaw weather saves plants.
