Fruit Tree Pruning Starts With Where the Crop Forms

Every fruit tree keeps its crop in one of two places, and the two want opposite treatment.

Apples and pears fruit on spurs, which are stubby side branches that lengthen less than an inch a year and sit on wood at least two years old. The wood carrying your apples is older than the shoots around it.

A spur is not permanent. It lives a long time, but its productive life is usually no more than eight to ten years, after which the same stubby branch keeps flowering weakly and setting little.

An old tree with a poor crop often has plenty of spurs and no young ones.

Peaches, nectarines and apricots do the reverse. Their flower buds form on shoots grown the previous summer, so the crop rides on one-year wood and moves outward every year.

Last summer's growth is this summer's harvest.

Plums and cherries sit across the line. Both set on spurs, and plums also carry a share on younger wood depending on the variety, which is why plum advice sounds contradictory wherever you read it.

The practical difference is what a careless cut costs.

Shortening every young shoot on an apple removes almost nothing the tree needed. The same afternoon's work on a peach removes the crop.

Before deciding how hard to prune, measure what the tree did last year.

Last season's growth starts at a narrow band of closely spaced rings partway along each shoot, left behind when the bud opened.

Bark is older and grayer on the trunk side of that band and smoother beyond it.

Everything past the band is one year old.

A stone fruit tree needs 12 to 18 inches of that growth each season to carry a decent crop. Measure three or four shoots around the tree rather than the one nearest the path.

Six inches of growth is not a pruning problem. It is a tree short of water, feed or root room, and cutting it harder makes a weak tree spend what it has on replacing branches.

Growth far over the range says the opposite. Upright shoots four to seven feet long are a tree investing in timber instead of fruit, and those are the ones to remove.

No equivalent number exists for apples, because the crop sits on older wood. On an apple the shoot length tells you about vigor, not about next year's harvest.

There are only two cuts, and the tree answers them very differently.

A thinning cut takes a whole shoot out at the point where it joins something else.

Nothing is left to regrow from, and the cut does not invigorate the tree the way other cuts do.

Light and air move into the gap and stay there.

A heading cut removes only the end of a shoot. The buds below the cut wake up, which is exactly why a shortened branch answers with three or four new shoots where one grew before.

That response is the source of most disappointing pruning. Somebody shortens every long branch to tidy the tree, and by August the tree is denser than it was in February.

Most of a yield job on an established tree is therefore thinning cuts. The aim is to get light onto the fruiting wood, and heading cuts add wood in the way of that light.

Heading cuts still have two proper jobs. They build the frame of a young tree, and they renew shoots on stone fruit, where new wood is the crop rather than an obstacle to it.

Light is the other half of yield. Fruit ripening in shade stays small and colors poorly, and the wood that never sees sun stops setting altogether.

Two frameworks do the job, and the species chooses which. Peach, plum and tart cherry grow naturally into a vase, so they are trained to an open center with three or four scaffold limbs set around the trunk at the compass points and nothing in the middle.

Apples and pears keep a single upright stem and take a central leader, with two or three tiers of scaffold branches spaced up it. A dwarf tree usually needs only two tiers.

Angles decide whether the frame holds.

A crotch between 45 and 90 degrees carries weight well, and on an apple the branch to keep sits about 30 degrees above horizontal.

Narrow upright forks tear out under a heavy crop.

Spacing decides whether light gets in. On a leader tree the lowest branch of the second tier sits at least 24 inches above the top branch of the tier under it, which leaves a window rather than a wall.

Water sprouts undo all of it. Those vertical shoots, some of them four to seven feet long, carry almost no fruit and shade the middle of the tree, so they come out at the base every year.

Prune fruit trees in late winter is the most repeated line in gardening, and it is an apple rule wearing a bigger hat.

For apples it holds. They are cut in the dormant period, late winter into early spring, with March and April named as the best months in cold regions.

Stone fruit is a different tree. Penn State tells home growers not to prune peach, plum or tart cherry from January through March, because a cut made into cold wet weather sits open while the tree can do nothing about it.

Those species are pruned from just before bloom until about two weeks after petal fall. The tree is awake, the wound closes quickly, and the wet winter diseases that enter through fresh cuts have less to work with.

Sweet cherry is later again, cut after it has fruited or in early July.

Order matters inside the dormant season too. Prune the latest blooming trees first and the earliest blooming last, since a cut is least likely to break dormancy on a tree that was going to wake up late anyway.

Summer pruning has a hard stop at the end of July. Cuts after that push soft growth into autumn, and soft growth meets the first frost unhardened.

A branch loaded end to end is not a good crop. It is one crop's worth of sugar divided too many ways.

Thin while the fruit is about the size of a nickel. The tree is still deciding how much to invest in each one, and taking the extras off early is what redirects that investment rather than wasting it.

Leave the survivors roughly 6 to 8 inches apart along the branch. On an apple that often means reducing a cluster of five to a single fruit and accepting how wrong it feels at the time.

Weight is the other reason. A fully loaded limb can snap before harvest, and a torn limb costs the fruit and the branch that would have carried next year's.

Thinning is the step home growers skip, and it changes fruit size more than any cut made in winter. It is also the fastest of the jobs on this page.

Skipping it has a second cost that arrives later. A tree allowed to overload one summer often takes the following year off, which is where the pattern of one heavy year and one bare year comes from.

Four mistakes cost a season rather than a branch, and all four look like diligence at the time.

The first is tidying a peach. Shortening every one-year shoot removes the flower buds that were going to be the crop, and the tree looks neat all summer with nothing on it.

The second is doing everything in one winter.

A drastic cut means greatly reducing every other cut in the tree that year, because hard pruning is answered with wood.

Spread a renovation across two or three years instead.

The third is fighting a tree that is finished. Trees left unmanaged for several years are generally not reclaimable, and a young replacement will out-fruit the rescue attempt long before the rescue succeeds.

The fourth is a late summer cut. Anything after the end of July pushes growth that meets the frost soft, and the damage shows up the following spring as dieback.

None of these is fixed by cutting more carefully. Each is fixed by stopping earlier.