Autumn-planted trees are at their most exposed right now. The roots have not knitted into the surrounding soil yet, the ground is cycling through freeze and thaw, and rabbits are working through plantings because winter forage is short. You will not always see the damage until spring growth starts, and by then it is too late to prevent it. Walk your newly planted stock now: firm anything that has heaved and make sure guards are in place before the next hard frost.

What frost heave does to a newly planted tree

Frost heave happens when water in the soil freezes and expands, pushing the surface upward. A recently planted tree has no established root structure holding it down, so the rootball lifts with the soil. In a single hard frost, the stem can rise several centimetres above the surrounding ground. When a thaw follows, the soil settles back but the rootball often does not come fully down with it, leaving air pockets around the roots. Those pockets dry out and then freeze again in the next cold spell. Each cycle adds stress to a root system that is already working to establish.

The problem is worst on clay soils, which hold more water and expand further on freezing. Lighter soils are less prone to heave but offer less insulation against hard frosts, so do not assume a sandy site is safe.

How to firm a lifted rootball

Look at the base of each tree. If the rootball has heaved, you will see it sitting slightly proud of the surrounding soil, sometimes with a visible gap at the base of the stem. Press steadily around the perimeter of the rootball with your boot to firm it back down. Work around the edge rather than stamping directly on top. If the ground is frozen solid, wait for a brief thaw; forcing a frozen rootball downward when the soil has no give can snap feeder roots.

Check the stake and tie while you are there. A tree that has heaved once will often have loosened its stake. The tie should hold the stem without cutting into the bark; a small amount of flex is fine and helps with trunk development. Top up the mulch ring if it has been disturbed, aiming for about 75 mm of bark chip over the rootball area, kept clear of the stem itself. Mulch reduces freeze-thaw cycling and cuts down on grass competition, which slows establishment in amenity plantings.

Rabbit browsing: the damage and how to stop it

Rabbits strip bark from young tree stems at ground level and up to about 50 cm above it. In winter, when grass and other forage is scarce, they work through plantings methodically. The signs are clear: smooth pale patches where the bark has been grazed, usually with a clean line at the top where the rabbit reached its limit.

If a rabbit removes bark all the way round the stem, the tree dies above that point. The layer of tissue that carries sugars from the leaves down to the roots has been severed, and nothing you do in spring will fix it. Fit guards before this happens, not after.

Fitting and checking tree guards

Spiral guards are the standard choice for whips and feathered trees. They allow air movement around the stem and are quick to fit. Most reach 50 to 60 cm, which covers the zone where rabbits typically graze. On sites with heavy rabbit pressure, or where larger-stemmed stock is at risk, a rigid mesh tube or solid tree shelter gives more reliable protection. Run a stake through the shelter into the ground so it stays upright; a guard lying on the soil beside the tree is not protecting anything.

On existing autumn plantings, check that guards have not been knocked over or loosened by wind and frost movement. Also check that spirals fitted in previous seasons are not starting to constrict the stem. A guard that wrapped easily around a 20 mm stem two years ago may now be cutting into bark that has thickened considerably.

Hares browse higher than rabbits, often reaching 90 cm or more, and voles damage stems at or below ground level where most guards do not reach. If vole damage is suspected, look for fine gnaw marks low on the stem or on exposed roots near the soil surface. Standard spirals and shelters will not help there.

Did you know? A rabbit can fully ringbark a young tree in a single night. Once the phloem layer is severed all the way round the stem, the tree dies above that point regardless of how healthy the roots are.

Frequently asked questions

How do I know if a newly planted tree has been frost heaved?

Look at the base of the stem. If the rootball is sitting proud of the surrounding soil, or there is a visible gap between the stem and the ground, the tree has likely heaved. The stake will often have loosened at the same time.

What height tree guard do I need to protect against rabbits?

Rabbits browse up to around 50 cm above ground level, so a standard spiral guard or tree shelter of 60 cm is usually sufficient. If hares are present on site, you will need protection of at least 90 cm.

Can I firm a frost-heaved tree back into the ground?

Yes, provided the soil is not frozen solid. Press steadily around the perimeter of the rootball rather than stamping directly on top. Re-firm the stake and tie at the same time, and top up the mulch ring if it has been disturbed.

When should spiral tree guards be removed?

After two to three growing seasons, before the expanding stem is constricted. Check the fit each year. A spiral that wrapped around a 20 mm stem in year one can cause bark damage if left as the stem thickens to 40 mm or more.

Do standard tree guards protect against vole damage?

No. Voles damage bark at or just below ground level, where spiral guards and tree shelters do not reach. Wire mesh pegged flat around the base of the stem can help on sites where voles are a known problem.