How to protect shrubs from winter burn and snow damage

Protect shrubs in late fall, before the ground freezes. Water them deeply once a week until the soil locks up. Spread 2 to 4 inches (5 to 10 cm) of mulch over the roots, and keep it a few inches back from the stems. Set a burlap screen on the windward side of evergreens that brown in winter. Tie upright evergreens loosely with soft twine so snow cannot split them. Never seal a shrub in plastic. Remove screens and ties in spring.

Short on time? Do two jobs today. Water the root zone and add mulch. Those two help every shrub in the yard.

Which shrubs need winter protection

Not every shrub needs help. Bare deciduous shrubs like lilac and spirea handle cold well in their zone. The shrubs at risk fall into three groups.

Broadleaf evergreens come first. These include boxwood (Buxus spp.), rhododendron (Rhododendron spp.), and holly (Ilex spp.). They keep their leaves all winter, so they keep losing water all winter. My post on Japanese boxwood covers one common example.

Upright evergreens come second. Arborvitae (Thuja occidentalis) and upright yew (Taxus spp.) have many stems that grow straight up. Heavy snow pushes those stems apart.

Shrubs near the edge of their hardiness come third. If a plant is rated for your zone and no colder, give it extra care. If you do not know your zone, how to find your growing zone shows how to check.

New shrubs need protection most. Their roots have not spread, and they cannot pull much water from cold soil. Protect any shrub planted in the last two years.

What winter burn is and why it happens

Winter burn is browning on evergreen leaves and needles. It shows up in late winter or early spring. The tips turn tan or red-brown first. In bad cases, whole branches brown.

The cause is water loss. On sunny or windy days, evergreen leaves lose moisture. When the soil is frozen, the roots cannot send more water up. The leaves dry out. University extension guides on winter injury describe this as the main reason evergreens brown in winter.

Two things reduce the problem. Moist soil going into winter gives the plant a water supply. A windbreak lowers how much moisture the wind pulls from the leaves.

Water deeply before the freeze

Dry roots make winter burn worse. Soak the soil under each shrub once a week in fall if rain has been light. Keep going until the ground freezes. Water the whole area under the branches, not only the base.

A new shrub needs a slow soak. Set a hose at a trickle for 20 to 30 minutes. Evergreens matter most here, because they lose water in winter and deciduous shrubs do not.

Stop fertilizing in late summer. Fertilizer pushes soft new growth, and frost kills it.

Mulch the root zone

Mulch holds moisture and slows the swings between frozen and thawed soil. Wait until the top of the soil is cool, then spread 2 to 4 inches (5 to 10 cm) over the root zone. Shredded bark and shredded leaves both work. My post on mulching tips covers depth and materials.

Pull the mulch 3 to 4 inches (8 to 10 cm) away from the stems. A pile against the bark gives mice and voles a warm place to nest. They chew bark all winter. Rake your leaves before you mulch, and my fall yard clean up checklist helps you plan the rest of the work.

Build a burlap screen

A burlap screen blocks wind and some sun. Use it for boxwood, rhododendron, and any evergreen that browned last winter. It also works for shrubs near a road, because it blocks salt spray.

Push three or four wooden stakes into the ground around the shrub. Set them outside the branches, so nothing touches the leaves. Staple or tie burlap to the stakes. Cover the windward side first. In most areas, that is the west or north side. A shrub in full winter sun also benefits from cover on the south side.

Leave the top open. Air and light need to reach the plant. A fully wrapped shrub can heat up on a sunny day and then freeze at night.

Do not use plastic. Plastic traps moisture and heat against the leaves. Burlap breathes.

Put the screen up in November, after a few hard frosts and before the ground freezes. Stakes go in easier before the soil locks up.

Tie up shrubs that split under snow

Wet snow weighs a lot. It bends the stems of arborvitae and upright yew outward, and the stems may not spring back. Tie the stems before the first big storm.

Use soft twine, strips of old cloth, or stretchy tree tape. Start near the base and spiral upward. Pull the stems in gently until they sit close to the center. Keep the wrap snug but loose enough that you can slide a hand under it. Wire cuts bark, so skip it.

For a shrub that gets heavy snow from a roof, build a small A-frame of boards over it. The roof of the frame sheds snow and ice to the sides.

After a storm, brush snow off with a broom. Push upward from underneath with a gentle lift. Leave ice alone. Branches coated in ice snap if you hit them, and they thaw on their own.

Should you spray an anti-desiccant

Anti-desiccant sprays coat evergreen leaves with a thin film that slows water loss. Garden centers sell them in fall. Extension results on how well they work are mixed. Some tests show a small benefit and others show none. The film also wears off during winter.

If you try one, read the label. Most call for a day above 40°F (4°C) with no rain in the forecast. Do not spray a stressed or dry plant. Water first. Burlap and deep watering give a more reliable result, so do those first.

Protect tender shrubs

Shrubs at the edge of their zone need a warm blanket around the base. After the ground cools, make a cage of chicken wire or hardware cloth around the shrub. Fill it with dry shredded leaves or straw. The fill protects the lower stems and buds. Keep the fill dry, because wet leaves rot. Cover the top of the cage with a board or a cap of burlap to keep rain out.

Roses need the same kind of care. My post on rose care in fall has the steps. For young fruit trees, see how to protect young trees from winter damage.

Check your shrubs in spring

Remove burlap, ties, and cages in early spring, once the hard freezes pass. For most cold zones, that is late March to April. Leave stakes in place if you plan to reuse them next fall.

Wait before you prune brown leaves. Evergreens often leaf out again from buds under the browned tips. Scratch a twig with a fingernail. Green under the bark means the branch is alive. Prune only the branches that stay brown after new growth starts in May. Water in dry spells, and the plant recovers on its own.