How should I train a young walnut tree?

Training decides whether an orchard comes into production with a sound, harvestable canopy or with years of corrective work ahead of it. The objective is not to make every tree look identical.

It is to establish one leader, enough clearance for your machinery, strong attachments, and a canopy that fits the orchard system. Everything else is optional.

If a cut does not solve a health, safety, access, structural or planned canopy problem, leave the wood.

Young walnuts respond to cuts. Heading concentrates growth below the cut; thinning removes a competing or badly placed branch without provoking the same flush of replacement shoots. That is why repeated heading tends to create the very regrowth that demands more pruning next year. In the establishment years, keep the tree growing, keep useful leaf area and cropwood, and make only the cuts that guide the permanent structure.

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Choose one training system, and stay with it

Young walnuts can be trained successfully under either of the two systems below. Pick one for each block and stay with it. Do not turn a no-heading block into a headed one because a few trees look untidy, and do not keep a defective leader in order to comply with a no-heading rule.

Throughout this chapter, central leader means one dominant main trunk. Modified central leader is the minimum-pruning system, in which that trunk establishes the scaffold framework before the crown broadens.

What the research actually shows

The evidence supports a light hand in young orchards. University of California trials in several lateral-bearing varieties found that unheaded trees generally produced higher early yields and, from about the fourth year onward, yields similar to minimally pruned trees. Heavily pruned trees were smaller and yielded less early on. A two-year study on Fernor likewise found higher cumulative yield from unpruned, unheaded trees.

None of this means that every variety, site, spacing or nursery tree should be left unheaded. It means that routine heading is not a substitute for a training plan.

It is also worth knowing that this is not a new position for us: the same University of California work sits behind the answer on our Howard page, where an eight-year hedgerow trial brought trees into bearing without annual pruning and found no significant difference in height, nut quality or cumulative yield after eight years.

The decision is made at planting, not after

This is the part that catches people out. Heading the nursery tree when it goes into the ground commits the block to a headed, scaffold-based tree. You cannot decide in the second dormant season to run a no-heading block if the leader was cut to knee height at planting; there is no leader left to leave alone.

So the system is chosen before the trees arrive, and it is chosen together with three other things: the finished height and quality of the nursery tree you are buying, the clearance your harvester and mower need, and whether the block is standard-spaced or a hedgerow. Settle those four together and the rest of this chapter is a set of small decisions. Settle them one at a time, in the field, and they will contradict each other.

Understand the wood before you cut

A thinning cut removes a branch at its origin, or back to a suitable lateral. A heading cut removes the end of a shoot or branch and usually releases several buds below the cut.

In young walnuts, head only where the system you chose calls for it. Do not head a leader to solve a support problem — that is what a stake is for — and do not shorten productive shoots because they look too long.

Protect next year's fruiting wood

Walnut varieties differ in where they carry their crop, and the difference decides what a cut costs you.

Every variety we produce except Franquette is lateral bearing, which is exactly why heading matters more here than it does in a traditional orchard. The figures below are the ones published on our own variety pages:

Fernette is not listed separately because no distinct bearing habit is recorded for it; it closely resembles Fernor and is grown here as Fernor's pollenizer. Chapter 3 covers what these habits mean when you are choosing a variety in the first place.

Never tell a crew to shorten all the productive shoots. Decide first what each shoot is: fruiting wood, replacement wood, permanent framework, or an unwanted upright competitor. Those four get four different answers, and only the last one is always cut.

Where the variety record and what you see in the field disagree, it is almost always safer to leave a questionable shoot for another season than to remove next year's crop positions on an assumption.

The no-heading system

Use no-heading only where the nursery tree has a sound scion leader and you already know the trunk and clearance heights the block needs. It is not an instruction to leave a poor tree unchanged.

An unheaded tree builds its framework by extension and lateral branching rather than by repeated cuts. Individual shoots commonly alternate between years of strong extension and years of short side growth. The short years are part of the normal pattern, not evidence that the tree has stalled. Your job is to preserve that pattern where it suits the block, and to correct a double leader, a weak fork or a real access problem before it becomes expensive.

At planting

A tree suited to no-heading has a sound leader — straight, or correctable — a healthy graft union, no serious transport damage, and enough leader height for the orchard system.

When the leader breaks, freezes or dies

Treat leader failure as a training problem with a deadline, not as damage to be tidied up.

Do not strip every small lateral and leaf from around an injury. Remove only the shoots that compete directly with the chosen leader or get in the way of training it — the rest are feeding the repair.

The first growing season

The job is one healthy leader, protected trunk tissue, and no permanent double leader. Inspect during active growth and correct a competing upright while it is still small enough to rub off.

Do not tip a sound leader to slow it down, and do not restrict water to slow the tree. If the support is the problem, extend the stake. If growth is unusually strong or unusually weak, the answer is in the block, not on the tree: review irrigation, nitrogen, soil variation, crop load, and root or disease problems before you reach for the secateurs. Chapters 6 and 8 cover the first two.

Staking, and knowing when to take it away

A stake is temporary support, not part of the permanent tree. Check the ties after wind and as the trunk expands: they have to hold the leader without rubbing, without tightening, and without preventing the normal movement that builds trunk strength in the first place.

If the tree leans, the leader bends sharply, or the base rocks in wind, re-tie loosely and fix the underlying cause — weak trunk, poor stake placement, wet soil, root damage or an unbalanced canopy — before trying again. Never leave an unused tie around the trunk. It will be found years later, buried in the bark.

The first dormant season

Prune only once the local frost risk and the disease-weather assessment allow it. Then, in order:

1. Keep the selected leader unheaded, if it is sound.
2. Remove upper laterals only where they compete with the leader, or make weak, crowded attachments above the planned scaffold zone.
3. Above the intended scaffold zone, rub off a problematic necked bud where a viable secondary bud sits below it — that favours the secondary bud and a wider crotch. Do not remove every bud.
4. Extend or adjust the support if the leader cannot stay upright in the wind you expect.

Low, non-vigorous laterals can earn their keep by shading the trunk and building caliper, provided they do not interfere with clearance, equipment or the leader's dominance. Treat them as temporary from the start, and decide now when they will come off.

The second and third seasons

Permanent clearance is about 1.2 to 1.5 m in standard-spaced orchards and 0.9 to 1.2 m in hedgerows. Those are starting points. Set the real height from the shaker, mower, sprayer and harvest equipment actually used in the block — chapter 4 covers which layout you are in.

At the second dormant pass, remove branches below permanent clearance. A low branch survives only if it is a non-vigorous temporary branch kept for shade or caliper, does not interfere with equipment or the leader, and has a clear removal date. Keep the leader and the permanent scaffolds unheaded. Remove a genuine narrow, included-bark fork or an equal-strength upright competitor before it turns into a large defect — but do not remove normal wide-angled laterals simply because they are not perfectly arranged.

By the third year, short side growth on an unheaded tree is likely to be part of its normal extension-and-branching pattern. On its own it does not indicate weak vigour and it does not justify heading. Compare it against irrigation, nutrition, soil, crop load and the neighbouring trees before you cut anything.

At the third dormant pass, remove only a branch that blocks equipment or safety, is dead, broken or diagnosed diseased, is a structural defect likely to worsen, or sits below permanent clearance. Do not head a scaffold because it made a long extension shoot — decide first whether that shoot is productive one-year-old wood, planned framework extension, or an unwanted upright.

The minimum-pruning system

This is the alternative: a modified central leader, where a headed leader establishes the scaffold framework and the crown then develops around it. Use it where you have chosen a headed, scaffold-based tree and the crew knows the variety, the vigour, the spacing and the clearance height.

The shape of it is a leader of at least 2.1 to 2.4 m before heading in standard-spaced trees, four to six primary scaffolds selected over the second and third years, and those scaffolds distributed around the trunk rather than in opposite pairs.

In the early years, select the leader first, then select the scaffolds as they reveal themselves. Favour branches that are well attached, adequately separated up the trunk, and spread around it. Remove a competing fork early, while a small thinning cut still solves the problem, rather than waiting until the tree carries two equal stems or a heavy, weakly attached limb. Leave useful small wood that is neither crowded nor in the way — it contributes to early canopy development and to early production.

Watch: the first pruning after planting

Almost everything above happens in the dormant season, because that is when the structural decisions get made. But the chapter also asks you to inspect during active growth and deal with a competing upright while it is still small — and that summer visit is the one most growers are least sure about. It is easy to read about; it is harder to know how much to take off when you are standing in front of the tree with the secateurs in your hand.

So here is ours. We filmed a young walnut being pruned for the first time after planting: the June work on a tree that went into the ground the previous November or March, which is usually called the first summer pruning.

The video is also the shortest answer to the question this chapter keeps returning to. Watch how little wood actually comes off, and how specific each cut is. Nobody in that footage is tidying the tree up.

When training is finished

Training is complete when the tree has the structure its orchard system needs — not when it reaches a particular age. The tree is ready to move from training to corrective pruning when it has all six of these:

Once those are met, stop trying to engineer the tree. From then on, prune for health, safety, machine access, disease, a structural defect likely to worsen, or a genuine light and cropwood problem. Do not prune every tree because the block has reached a calendar age.

Before the crew starts

When the crew should stop and ask

• The system for the block is unclear.
• A heading decision depends on a variety or bearing habit nobody is sure of.
• A leader repair could leave a permanent fork.
• A tree has no viable scion leader.
• The required clearance is not known.

A walk through the block before and after the work is usually enough to keep the plan on track. Before pruning, look at several trees across the range of vigour and decide what a good finished tree looks like in this block. After pruning, check that the leader is still dominant, that the clearance matches the machinery, that every temporary low limb has a purpose, and that no stake or tie is rubbing a trunk. These are not paperwork; they are the two checks that stop a sound system being undone one cut at a time.

Mistakes worth avoiding

• Heading a sound nursery tree when the chosen system is no-heading.
• Leaving a damaged, weak or too-short leader uncorrected in order to follow a no-heading rule.
• Treating a guide number as machinery clearance. Measure your own equipment.
• Allowing two equal leaders after leader damage.
• Tying a leader tightly, leaving an unused tie on the trunk, or removing support before the tree can stand alone.
• Treating all one-year-old shoots as expendable without checking the bearing habit and what each shoot is doing.
• Repeating a dormant heading cut to remove the regrowth the previous heading cut created.
• Removing temporary low branches without deciding whether trunk shade or caliper support is still needed.
• Pruning by calendar without reviewing frost, weather, disease and field conditions.

The lesson underneath all of them is a short one: choose the system that suits the block, protect future cropwood, correct real structural and access problems early, and resist every cut that lacks a clear purpose. If you are not sure which system your block should be in, ask us before the trees are planted — it is the cheapest conversation in the whole orchard.