Planting Fruit Trees in March: Keep the Graft Union Above Soil Level

Anyone planting an apple, cherry or apricot tree in March or April dreams of fragrant blossom and fruit from their own garden. Yet the reality is often the opposite: the tree struggles, produces scarcely any new growth, fails to flower – and no one understands why. The cause is frequently not the tree itself, but a few crucial centimetres during planting.

The most common planting trap: fruit trees planted too deeply

Well intentioned, but disastrous in practice

Many gardeners assume that a tree needs to sit as deeply and securely in the ground as possible. They therefore dig a generously sized planting hole, pile soil firmly around the base of the trunk and press everything down tightly. It sounds sensible, but it is highly dangerous for fruit trees.

“Anyone who covers the base of the trunk and the graft union with soil is, quite literally, depriving their fruit tree of air.”

As a result, oxygen exchange around the tree’s sensitive base is severely restricted, moisture builds up and the tree remains permanently damp. This is precisely the area that is not designed to cope with such conditions.

Why wet soil against the trunk is so risky

The bark on the trunk is very different from the root sections. Roots can tolerate constantly moist soil because they are adapted to it. Trunk bark, however, reacts badly to continuous wetness.

When soil remains piled directly against the trunk, the following can happen:

• the bark begins to soften and swell;
• damage develops in the concealed wood;
• fungi and rot-causing pathogens enter the tree;
• the transport tissues that carry water and nutrients are destroyed.

At first, the tree may appear perfectly normal from the outside. Below ground, however, the trunk gradually rots away. Shoots above the damaged section receive less and less sap, until the tree grows only weakly or dies entirely.

The key point on the trunk: finding the graft union

How to identify the sensitive areas on a young fruit tree

Most fruit trees bought from nurseries are grafted. In other words, a robust rootstock – the root section – is joined to a high-quality fruiting variety. This connection is usually clearly visible on the trunk.

Two points are particularly important:

• Root collar (trunk base): the transition between root and trunk, where the root tissue ends and the actual trunk begins.
• Graft union: a few centimetres higher up, visible as a swelling, scar or slight bend in the wood – this is where the chosen variety was grafted on.

This “scar” will later form the productive crown. It must never disappear beneath the soil.

Why the graft union must remain exposed

“The graft union is the heart of your fruit tree – if it disappears into the soil, the tree loses its strengths.”

If the graft union ends up below ground, the upper part of the tree may try to form roots of its own. That might sound beneficial at first, but it is not: the advantages provided by the rootstock – frost hardiness, disease resistance and more restrained growth for small gardens – are lost.

Gardeners refer to this as own-rooting: the grafted variety becomes independent of its rootstock. The consequences include:

• the tree often grows more wildly and becomes harder to manage;
• flower formation is noticeably delayed;
• yields suffer;
• susceptibility to disease increases.

Rather than putting its energy into flower buds and fruit, the tree is busy trying to survive. Very little then remains of that well-intentioned start.

How to plant fruit trees correctly in March

The golden rule for planting height

The most important practical rule is this: after planting, the graft union must sit 5 to 10 centimetres above the final soil level. The root collar itself should remain just above ground level or level with the surface, but it must not be buried.

“Keep the trunk base clear and the graft union plainly visible – that is how fruit trees make a strong start in their new home.”

This keeps the sensitive area dry, exposed to sun and air, and protected from permanently wet soil. The tree can then direct all its spring energy into new growth and flowering.

A trick to prevent the soil sinking later

Freshly loosened soil contains plenty of air and settles considerably after a few weeks. If this is not allowed for, the tree may still end up planted too deeply.

A practical method is as follows:

• Build a small, firm mound of soil in the planting hole.
• Spread the roots out like a fan over this mound.
• Lay a straight cane or spade handle across the hole to mark the eventual soil level.
• While backfilling, check that the graft union remains 5–10 cm above this line.
• Firm the soil gently, but do not compact it until it is hard like concrete.

This ensures that the tree remains high enough even after the soil settles, keeping it at the correct level for years to come.

How to spot a “livingly buried” tree

Warning signs in the first and second growing years

Fruit trees with a root collar planted too deeply do not immediately show obvious distress. Symptoms develop gradually, especially in spring and early summer:

• short, weak new shoots;
• small, yellowish leaves;
• flower buds that dry out before opening;
• barely visible growth for a long time, as though the tree were “on pause”.

At the latest, if the second year again brings only sparse growth and no blossom, it is worth inspecting the very base of the trunk. You may already find that the graft union is disappearing just below the soil surface or is tightly covered with soil.

Rescue measure: uncover the trunk base

“If the damage has not progressed too far, a fruit tree planted too deeply can be saved by exposing its base.”

With a little care, such a tree can still be stabilised:

• Carefully remove soil from around the trunk using your hands or a small hand trowel.
• Create a shallow hollow around the trunk so that the root collar and graft union are visible and uncovered.
• Take care not to damage fine roots or scratch the bark.
• Position the watering basin slightly further away so that water does not run directly against the trunk.

The tree will usually respond to this relief with much stronger new growth and a healthier leaf colour the following spring. Even so, one or two years may pass before its first full flowering period – patience is worthwhile here.

Checklist: helping your fruit trees establish healthily in the garden

Check while backfilling the planting hole

Following a few basic rules makes it easy to avoid the usual mistakes. A short checklist is useful when planting:

• Position the graft union clearly above the eventual soil line.
• Do not press soil directly against the trunk; the bark must remain exposed.
• Form the watering hollow slightly away from the trunk so water cannot collect around the wood.
• Firm the soil only enough to keep the tree stable while retaining air in the ground.
• During the first few weeks, check regularly whether the tree has sunk.

Anyone who follows these points creates the foundation for vigorous roots and a robust crown.

What terms such as root collar and grafting mean

A brief look at fruit tree anatomy

The root collar is the point where the root joins the trunk. It is where the tree’s underground and above-ground parts meet. This zone is particularly sensitive to persistent wetness, frost and bark damage.

The graft union is created when a selected variety – for example, a flavoursome apple – is grafted onto a rootstock that copes well with the soil, climate and diseases. Without this technique, many modern fruit varieties would be difficult to grow reliably in a home garden.

That is exactly why the position of this scar in relation to the soil surface matters so much. If it is accidentally buried, the tree loses the very characteristics you intended to buy.

Practical examples for different locations

Slopes, heavy soils and container planting

On sloping ground, water tends to run off, so the risk of waterlogging is lower. Even there, however, the same rule applies: keep the trunk base clear and leave the graft union above soil level. In very heavy clay soils, it is worth adding a drainage layer or at least mixing in sand and compost so that water drains away more quickly.

Anyone growing fruit trees in containers, such as columnar fruit trees or trees on dwarfing rootstocks, needs to pay even closer attention: waterlogging develops more quickly in pots. A thick layer of broken clay pots at the bottom, high-quality structurally stable compost, and one firm principle will help: never pull soil over the root collar, even if the surface sinks a little over time.

Ultimately, success or failure depends not only on the variety, but also on paying attention to these few crucial centimetres of trunk. Those who keep an eye on them will see more than bare branches in spring: they will see a sea of blossom, followed later by baskets full of home-grown fruit.