Bare-root trees in autumn and protecting trunks from hares

Autumn is the best time to plant a tree or shrub, especially a bare-root one: the leaves have dropped, the plant loses almost no water, the soil is still warm and all its energy goes into the roots. By spring the tree wakes up already rooted. But autumn planting has a second half – winter. Once snow covers the grass, hares, roe deer and voles come for the bark of young trees.

Why autumn beats spring

In spring a new tree does everything at once: it opens its leaves, loses water through them and grows roots at the same time. In a dry May the roots cannot keep up with the leaves and the tree stands still for weeks. In autumn there are no leaves, almost no water loss, and the roots keep growing until the soil cools. Such a tree starts growing earlier in spring and copes better with the first dry spell.

The key is not to leave it too late: in cold soil roots grow slowly. Plant soon after leaf fall so that several weeks remain before the ground freezes; in Estonia that usually means October. Stone fruit (cherries and plums) on cold, wet sites is safer planted in spring.

Bare-root trees

A bare-root tree is lifted at the nursery after leaf fall and sold without a pot or root ball. It costs less than a container plant, and you can see the whole root system. The one drawback: bare roots dry out quickly, and dried roots are the main reason such a tree fails.

• When buying – plenty of fine roots, no tears, cut ends pale and moist. Dry, brittle or blackened roots are a bad sign.
• On the way home – roots in a damp bag, out of the wind and sun.
• Before planting – soak the roots in a bucket of water for half an hour to a couple of hours.
• If you cannot plant straight away – heel the tree in at an angle in a shady spot and cover the roots with moist soil.

Planting step by step

1. The hole – two to three times as wide as the roots, but no deeper. Loose soil at the bottom of a deep hole settles and the tree sinks with it.
2. The stake – drive it in before planting, on the windward side, so you do not spear a root. Trees over a metre tall need one.
3. The roots – cut broken roots back to healthy tissue. Set the tree on a small mound of soil in the hole and spread the roots out and down.
4. Depth – the root collar (where the roots begin) sits level with the soil or a couple of centimetres above it. On apples and pears grafted onto dwarfing rootstocks, the graft union stays 5–10 cm above the ground; more in our article on columnar apple trees. Lay a spade handle across the hole to see where the soil level will be.
5. Backfilling – fertile soil mixed with compost, shaking the tree gently now and then and firming carefully with your foot. No nitrogen or fresh manure is needed in autumn; mix a phosphorus-potassium fertiliser into the soil so the granules do not touch the roots. More in our article on nitrogen-free autumn fertilisers.
6. Watering – 10–20 litres straight away, even if the soil is wet from rain: the water removes air pockets around the roots.
7. Tying – a soft tie in a loose figure of eight so it does not rub the bark. Take the stake away after 2–3 years.
8. Mulch – 5–7 cm of compost or bark, leaving a clear ring of about 10 cm around the trunk: voles overwinter in mulch piled against the bark.

Who eats bark in winter

While there is grass, hares and roe deer mostly leave bark alone. Once snow covers their food, they turn to young trees: fruit and ornamental trees, and among conifers yews, young larches and Douglas firs, and rarer junipers.

The height of the damage rises with the snow: standing on a deep, hard crust a hare reaches the lowest branches, so fit protection with height to spare. The marks show who has been there:

• Hares strip bark in patches, leaving bits of bark, pale inner bark or the green layer beneath. Such a tree usually survives.
• Mice and voles work at ground level and below, under the snow and in mulch, and often take the bark off in a complete ring. A closed ring kills the tree, because food travels from the leaves to the roots just under the bark. The tree may still leaf out in spring, then it dies.
• Roe deer browse shoots and buds and can gnaw bark too.

What actually protects

Trunk mesh

The most reliable protection is a cylinder of metal mesh 1–1.5 m high, set with a gap from the bark. Bury the bottom edge 10–15 cm into the soil so voles cannot get underneath; against mice and voles the mesh should be about 6 mm. Fit it before the first snow. Trunk mesh is currently out of stock with us; a delivery is on its way.

Plantskydd repellent

A Swedish repellent based on dried blood: hares and deer smell it and do not even try the bark. Treat the trunk right from the base and the lower branches, which also covers the part above the mesh. Three rules:

• Dry bark – it will not stick to wet bark.
• Above freezing – do not apply in frost.
• A day without rain – that is how long it takes to dry.

The easiest time is October–November, on a dry mild day. One more tip: in late autumn pull the mulch away from the trunk and cut the grass back for about 60 cm around the tree – voles dislike open ground.

Whitewash is for sun, not hares

On sunny days in February and March, the sun warms dark bark on the south and south-west side, the tissue beneath it wakes, and the night frost kills it. That is how sunscald and frost cracks appear. A white coat reflects the sun; young, thin-barked trees need it most. Whitewash in late autumn and touch it up in February. But whitewash is neither a barrier nor a repellent: mesh and Plantskydd protect from hares, whitewash from the sun, and a garden needs both.

What not to do

• Don’t dig the hole deeper than the roots or bury the root collar and graft union
• Don’t leave bare roots in the wind and sun, even for half an hour
• Don’t put fertiliser straight onto the roots or give nitrogen in autumn
• Don’t pile mulch against the trunk
• Don’t apply Plantskydd to wet bark or in frost

Frequently asked questions

Can I plant bare-root trees at the end of October?

Yes, as long as the ground is not frozen and a spade goes in easily. The later you plant, the less the roots grow before winter, so water and mulch late plantings without fail.

Does whitewash protect against hares?

No. Whitewash protects bark from sunscald and frost cracks in late winter. Against hares and roe deer you need trunk mesh and a scent repellent such as Plantskydd.

A hare has gnawed the bark – will the tree die?

If the bark is gone in patches, the tree usually recovers on its own. If it is gone in a full ring, food no longer reaches the roots; only bridge grafting in spring can save such a tree, and that is a job for an experienced gardener.

How long does Plantskydd last?

According to the manufacturer, up to 6 months on dormant plants. After long thaws and heavy rain, check the trees and reapply if needed on a dry day above freezing.

From our catalogue

Repellents are in the animal repellents section. Young trees are under fruit trees and berries.