Young fruit trees get hurt in winter three ways: an early freeze before they harden off, deep midwinter cold, and late-winter sun that thaws the trunk by day so it freezes again at night (southwest injury, or sunscald). We shut growth down in August, plant where cold air drains away, paint or guard trunks, keep 1/4 inch hardware cloth 18 to 24 inches above the snow line (University of Minnesota's number), and fence deer at 8 feet.
The three kinds of winter injury
Our friend Bob Purvis, who grows fruit in Homedale, Idaho, sorts cold injury into three situations.
- Early winter. A dry summer and a wet fall slow hardening off, and the base of the trunk can be badly hurt. In late October 2020, Missoula went from mild fall weather to -10 to -20F almost overnight, and it wiped out a lot of trees rated plenty hardy on paper because they hadn't gone dormant. We lost almost all our 1- to 3-year-old Bing cherries.
- Midwinter. Sheer cold, or a big mild spell that de-hardens trees before a sudden drop below zero. Purvis puts that damage anywhere from a little at 0F to fatal at -12F.
- Late winter. Sun heats the bark by day and it freezes at night. That's southwest injury, worst on young apples and pears.
Trees harden off from the twig tips back to the base of the trunk, so the trunk base is last to get ready. That's why, in zone 4 and colder, we taper the water from mid-August and stop by late August. After leaf drop, every tree gets one final drink to carry it through winter.
Plant where the cold drains away
For cold areas, the right variety comes first and site selection second. Avoid depressions and frost pockets, look for good air drainage and higher ground, and stay out of windy spots. Cold air is heavy. On clear, still nights it runs downhill like water and pools in low ground.
A yard can easily sit a half zone, sometimes a full zone, off the USDA map. A gentle south or east slope sheds cold air, elevation costs roughly 3 to 5F per 1,000 feet, and a south wall or driveway can buy you a half zone.
Roots are the weak link. They never get as hardy as the top of the tree. In freezing tests EMLA 7 roots died at about 20F soil temperature, and a good snowpack can hold the soil up to 20F warmer than bare ground. In -40F country we'd skip EMLA and Geneva stocks for Bud 118 or a seedling crab root (see our rootstock page).
Paint the trunk white
Paint young trunks white. On a sunny late-winter day the bark warms and the sap thaws, then it freezes at night and the bark sloughs off the wood. Utah State Extension says the sunny side of a trunk can run up to 77F warmer than the shady side. Purvis notes a girdled tree still leafs out, then dies quickly when its starved roots collapse.
Use white interior latex paint cut 1:1 with water. Utah State warns that exterior paint has antimicrobial additives that can hurt bark. Purvis paints from the ground up 3 to 4 feet in late summer, and the University of Tennessee paints in late fall on a day above 50F. We consider it an important practice on all fruit trees, and crucial on a sunscald-prone variety like Cortland.
Use light-colored guards and take them off in spring
For tender stone fruit in zone 4 (nectarines, peaches and some apricots), we set a tree guard 6 inches out from the trunk, leaving space for ground heat to rise around it. It protects against sunscald and cold winter wind chill. Don't let it stay wet and rot the trunk, and take it off in early April. From what we've seen, thicker wood is more prone to wind chill damage but more resilient to extreme lows.
Purvis puts white plastic spiral guards with holes on all young trees in November, against rabbits, voles and southwest injury. Stick to white or light colors: University of Minnesota Extension warns against brown paper wrap and black guards, which absorb heat. C.J. Walke of the Maine Organic Farmers and Gardeners Association takes spirals off in spring, since insects and disease hide under them. Utah State keeps guards on for 2 to 3 winters, and Purvis says a tree that survives three winters has very good odds from there.
Hardware cloth and bare ground for rabbits and voles
Rabbits are a serious problem when snow is deep, since they feed from the snow surface and the damage climbs with the snowpack (Iowa State). Wrap trunks in 1/4 inch hardware cloth reaching 18 to 24 inches above the snow line you expect, with the bottom 2 to 3 inches buried (University of Minnesota). Purvis figures a cylinder to about 3 feet, or a fence 2 feet above the deepest snow, and the problem fades as the bark thickens.
Voles feed mostly within 3 inches of the soil (Iowa State), and Purvis's best control is taking away their cover. Rutgers calls a vegetation-free zone under the trees the most important step, and buries hardware cloth at least 6 inches to stop voles. Clear weeds and grass within 2 feet of young trees in late fall (University of Minnesota), and pull bark mulch back from the trunk for winter (Iowa State).
Fence deer at 8 feet, or build two fences
Fence deer out at 8 feet if you can. The main orchard fruits aren't deer resistant: apples, plums, cherries and pears land in the "protect it" group on nearly every list behind our deer-resistant plants page. These are the options that work:
| Option | Size | Why it works |
|---|---|---|
| Woven wire fence | 8 ft | Deer easily jump 5 ft, many clear 6, some clear 7 and a very few clear 8 (Montana Fish, Wildlife and Parks) |
| Bob Purvis's fence | About 5.5 ft, with barbed wire or thin wood at 7 to 8 ft and barbed wire 6 in to 1 ft up | Deer won't test a fence or lean over it, a visual barrier puts them off, and the low wire stops them crawling under |
| Double fence | Two 5 ft fences, 4 to 5 ft apart | Deer can't do the high jump and the long jump at once (Montana FWP) |
| Cage around each tree | 5 ft tall (taller where snow gets deep), 3 to 5 ft out from the trunk | Montana FWP's spec for a fruit tree |
Repellents exist, but the best cut browsing only up to 60 percent (MSU Extension).
Dogs and squirrels
Dogs chew on young trunks, and Purvis's answer is the same hardware cloth cylinder. Squirrels go after ripe fruit instead, so they're more a summer problem than a winter one. Purvis found trapping worked best, for a while, since squirrels are territorial and ultimately come back. UC IPM calls keeping them out of fruit trees "virtually impossible," though netting can work where they have other food, and it helps to cut back limbs that bridge over from a roof. Purvis's squirrels went after his plums, apples and pears but hadn't taken to apricots, though he notes sweet-pit apricots like Harcot and Precious are highly attractive to squirrels.
Frost at bloom, and what 2026 showed us
The last cold of the year comes at bloom, and 2026 was a rough one across Montana. A grower friend in Gallatin Gateway saw 15F during bloom and got no fruit at all; even the chokecherry blossoms froze. Growers higher on the valley floor and up on the benches fared much better, cold air drainage most likely. A Bitterroot orchard lost about 30 percent of its blossoms, and at our place currants and gooseberries bore prolifically after their flower buds saw about 22F.
Thirty percent sounds worse than it is. Unless the fruit is clustered (cherries, grapes), most fruit tolerates 50 percent or more blossom loss with negligible effect on the crop; it acts as natural thinning. Utah State figures apples, pears and peaches need only 10 to 15 percent of their blossoms for a full crop, but cherries need over 50.
Related guides
- How we rate cold hardiness, and how to read our zone ratings
- Rootstocks for cold country, and why we use ours
- What to do when your bare-root trees arrive
Where this comes from
- Our planting guide (the winter section), our zone hardiness, rootstock, cold-hardiness calculator (the October 2020 freeze) and deer-resistant plants pages, and our Bing cherry and Cortland notes.
- Our 2026 season notes, including reports from growers in our network.
- Bob Purvis, Fruit Growing for Homeowners lecture notes and his NAFEX talk Apricots: A Wider Geographic Possibility (2006), minus his pesticide and repellent material.
- Our no-spray research brief: Utah State University, University of Minnesota, Iowa State University, Rutgers, University of Tennessee and UC IPM, and C.J. Walke of the Maine Organic Farmers and Gardeners Association. Deer figures: Montana Fish, Wildlife and Parks and Montana State University Extension, via our deer page.
Updated September 2026.