How to Protect Shrubs from Winter Damage

Winter damage at a glance

Burlap against wind and winter sun

Penn State explains winter burn: the ground freezes, the roots cannot take up water, and winter sun and wind keep drawing moisture out of the leaves. Evergreens do not go dormant, so they keep losing water all winter.

1. Set stakes, not wrapping. Penn State drives 4- to 5-foot stakes about 2 feet out from the drip line, either all round the plant or as a wall on the exposed sides, usually south and west.

2. Attach burlap or canvas to the stakes (Penn State).
3. Leave the top open. Both sources say so; Minnesota says surround the plant only if it has been injured on all sides.
4. Do not fill it with leaves. Penn State says that invites rodents, which eat the bark.
5. Take it down promptly in spring once the weather warms (Penn State).

Minnesota also suggests propping pine boughs or Christmas-tree greens against evergreens, which shade them and catch more snow. Penn State says barriers help most on new plantings and on plants rated only as hardy as your garden’s zone; plants hardier than your zone generally come through more easily. Check a shrub’s rating against your zone with the ZIP lookup below.

Water before the ground freezes

Minnesota says keep evergreens watered through the growing season and into fall, cut back slightly in September to let them harden off, then water thoroughly in October until freeze-up. Watering only in late fall does not help. If the fall has been dry, it says, water heavily before the ground freezes to reduce how deep the frost goes.

Penn State recommends deep, infrequent watering in dry fall spells, so the soil holds a reserve plants can use in brief winter thaws — but not so much that the soil is saturated when it freezes, which can rot roots. For a shrub planted this fall, the fall planting guide has the full first-winter watering schedule.

Mulch and snow

Minnesota says snow cover insulates plants from wind and deep cold, and that snow and mulch both keep soil warmer; a lack of snow is one of its listed causes of cold damage. Penn State says that without snow, mulch is a plant’s best friend: it keeps roots taking up water longer in fall and stops the freeze–thaw cycle once the ground is frozen. Minnesota says a 4- to 6-inch layer prevents frost from heaving shrubs and new plantings out of the ground.

Road and de-icing salt

• Do not plant trees and shrubs where salty runoff collects or close to streets with heavy salt spray (Minnesota).
• Burlap barriers may protect some plants from salt spray (Minnesota).
• Clear snow early and use the least salt needed, only where it is needed; keep it off grass and out of ditches where water collects (Minnesota).
• Try calcium chloride or calcium magnesium acetate instead (Minnesota).
• Near walks and roads, use more salt-tolerant plants. Minnesota’s examples are trees, Japanese tree lilac among them, and it warns that no plant is completely tolerant. The rose page notes Minnesota calls rugosa roses tolerant of road salt.

Heavy snow and ice

Minnesota says upright evergreens such as arborvitae and juniper, and plants with several stems, break most easily. Tie the leaders together with strips of carpet, strong cloth or nylon stockings, two-thirds of the way up above the weak forks, and take the ties off in spring so they do not girdle the stems. Pruning out competing leaders and weak forks reduces the damage in later winters.

Deer, rabbits and voles

• Remove cover. Minnesota says cut grass and other plants short within 2 feet of young trees in late fall, and clear brush piles where rabbits shelter.
• Fence shrubs against rabbits with hardware cloth, enclosing the lower branches as well as the trunk, with the base buried 2 to 3 inches (Minnesota). Check fenced beds so no rabbit is trapped inside.
• Fence against deer at 8 feet. Minnesota says deer can clear 12 feet with a run-up, and that starving deer will eat plants whatever the deterrent.
• Repellents make plants taste or smell bad. Minnesota says one application usually lasts the dormant season, but most deer repellents need reapplying after rain or irrigation.

Sunscald

Sunscald is mainly a tree problem: Minnesota describes sunken, cracked bark on the south or southwest side of young, newly planted and thin-barked trees, and prevents it with white tree guards from fall to spring. The fall planting guide covers guards for new trees.

If damage happens

Minnesota says brown evergreen foliage is most likely dead, but the buds, which are hardier than the leaves, often grow to fill the gaps. Wait until mid-spring before pruning; if the buds have not survived, prune dead branches back to living tissue, feed in early spring and water well through the season. Penn State says prune damaged parts in spring before new growth starts.

Common mistakes

• Wrapping burlap tight around the plant. Penn State sets it on stakes about 2 feet out.
• Stuffing leaves inside the burlap. Penn State says that draws rodents to the bark.
• Relying on anti-desiccant sprays. Minnesota says they are not effective.
• Watering only once, in late fall. Minnesota says that does not help; water through October to freeze-up.
• Pruning or feeding in late summer. Both sources say it pushes tender growth into winter.
• Piling salty snow on shrub beds. Minnesota says salt in the soil injures roots.
• Leaving snow ties on all year. Minnesota says remove them in spring.

In the South

We found no Southeast, Texas or Florida source on protecting shrubs in winter, so advice for the South here is limited. Both sources write for cold, snowy winters with frozen ground. For mild-winter areas, ask your county extension office.

Related

• ZIP code zone finder — your exact USDA zone, to check each shrub’s rating against
• When to Plant Trees and Shrubs in Fall, by Zone — a new planting’s first winter
• Hydrangea winter care — the old-wood hydrangeas whose flower buds spend winter on the stems
• How to Winterize Roses by Zone: Mounding, Mulch, Timing
• When to Cut Back Perennials in Fall, and What to Leave
• How to Prune Crape Myrtles Without Crape Murder
• Shrubs by zone: Hydrangea, Magnolia, Dogwood, Serviceberry, Crape myrtle, Rose, Azalea, Japanese maple, Lilac, Viburnum, Camellia, Gardenia, Forsythia, Spirea, Rose of Sharon, Weigela