What do I do if snow settles on my hedges and shrubs?

Why snow is a mechanical problem rather than a cold one, which plants need clearing and which are better left, and how to clear without snapping frozen wood.

Difficulty: beginner
Time: 25 min
Read: 4 min
Safety: caution

Short answer

Clear the top of hedges and the crowns of upright conifers first, because those hold the most and are permanently deformed by it. Lift the snow off from underneath a branch with a gloved hand or a soft brush so the branch rises as the load goes. Never knock downward and never shake — frozen wood is brittle and the impact snaps what the weight alone would not. Leave snow lying on low mounded plants, where it is insulation rather than load.

Snow rarely kills British garden plants by cold. It damages them by weight, and the damage is often permanent in a way that frost damage is not: a conifer splayed open for a week does not close up again, and a hedge whose top has opened stays open until it is renovated.

Safety

Do not clear snow from anything you cannot reach standing on the ground, and do not use a ladder in snow or ice. Snow-loaded branches release upward with real force when cleared, so keep your face and eyes out of the line. Anything overhead, at height or under tension is an arborist's job.

What settled snow does to a shrub and how to clear it

Step by step

Go out during the fall, not after it.The damage is done by accumulation. Clearing a hedge top once part-way through a heavy fall prevents far more than clearing it thoroughly the next morning.
Prioritise by shape.Flat horizontal surfaces collect the most: the top of a formal hedge, the crown of a columnar conifer, a topiary shape, a wide evergreen with layered branches. Anything domed or upright sheds snow itself.
Lift, do not knock.Work from beneath the branch with a gloved hand, a soft broom or a length of timber, and push upward so the snow slides off and the branch rises with it. This is the whole technique and it is the opposite of what people instinctively do.
Never shake a frozen plant.Frozen tissue is brittle. Shaking shatters buds and small wood, and the damage does not show until spring when the shoots fail to come.
Work along a hedge in sections.Start at one end and work along, taking the top first and then the sides. Half-clearing a hedge leaves an uneven load that can pull it sideways.
Leave low mounded and herbaceous plants alone.Snow lying on them insulates them from the much colder air above, and clearing it exposes them. This is genuinely better for the plant and it saves you the work.
Deal with what has already bent, in spring.Do not try to force a splayed conifer back into shape while it is frozen. Once it has thawed, tie the branches back in loosely with soft twine and leave them tied for a season; sometimes they recover and sometimes they do not.
Prevent it next winter on anything that splayed.A loose spiral of soft twine up a columnar conifer before winter holds it together under load and is far easier than reshaping it afterwards. Check it does not cut in as the plant grows.

Tips

Wet snow is dramatically heavier than dry powder. A fall at just above freezing is the one that breaks things, and it is worth going out for.
A second fall onto a first is the usual failure. If more snow is forecast, clear what is already there.
Snow sliding off a roof onto planting below does more damage than snow falling on it. Anything under a pitched roof edge is worth protecting or resiting.
If a hedge has already opened, tie it in and let it grow rather than cutting the damage out — cutting into the gap makes it permanent.

Common mistakes

Knocking snow downward off branches with a broom — You are adding an impact load to a branch that is already carrying more than it should, and the wood is frozen and brittle. This snaps far more branches than it saves.
Clearing snow off the ground and off low plants but not off the hedge top — It is exactly backwards. Snow on the ground and on low plants is harmless or helpful; snow on the top of a hedge is what causes lasting damage.
Waiting until the snow melts — Melting snow gets heavier before it goes, as it absorbs meltwater and consolidates. The worst load is often after the fall has stopped.

Questions people ask

Does snow damage plants by cold at all?

Rarely in Britain, and it more often protects them — a snow cover insulates the ground and the plants under it from the colder air above, which is why snow-covered crowns come through better than exposed ones in a hard freeze.

My conifer has splayed open. Will it recover?

Sometimes. Tie the branches back in loosely with soft twine once it has thawed and leave them for a full growing season; the plant may re-establish its shape. Old, heavy branches that have hinged at the trunk usually do not.

Should I clear snow off a greenhouse?

Yes, from the roof, because the load can break glazing bars and panes, and because snow lying on the glass cuts out the light plants inside need. Clear it from outside with a soft brush, not from within.