Fruit trees
It is very important to prune fruit trees properly. This means not simply removing branches but knowing the consequences of what you are doing. After all, your goal is to harvest as many healthy fruits as you can. This is why it would be a good idea to actually watch how this is done by someone with experience. Several places hold pruning workshops for this very purpose.
Index:
Pruning in general
During the first 3 to 4 years, pruning is aimed at developing the main framework of the tree. A one or two-year-old fruit tree usually has one small trunk (also known as the central leader) and a few side branches (also known as laterals). It is these laterals that will produce the fruiting arms on which the tree will eventually (when old enough) start flowering and producing fruit.
Depending on the variety’s vigour, the branches of most varieties are pruned during the tree’s dormant period. For certain kinds of trees such as cherries, plums and other stone fruits, this is done early in the autumn. As the trees matures, pruning is done primarily to retain the tree’s form and for rejuvenation. Particularly important at that stage is the open pruning of a tree that allows light and air in through the centre of the canopy.
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Apples and pears
For pome fruits such as apples and pears, the central leader and laterals are pruned more or less heavily during the first years. For young trees, winter pruning focuses mainly on achieving a good shape. Once the trees are properly shaped, maintenance pruning will usually be enough. This involves starting by removing any dead or diseased wood and then removing water shoots and branches that rub against one another.
Also important is to keep the canopy open. Somewhat older trees will need rejuvenation pruning. In places where a somewhat older branch sags sharply, a new shoot that grows fairly upright usually emerges. This is when the older branch will have to be pruned off just beyond that shoot.
If an old tree contains a lot of barren wood (without strong laterals), rejuvenation pruning, consisting of removing all of this will be necessary. Since this is a rather drastic operation, it would be advisable to spread out this kind of heavy pruning over a few years. And always remember to consider the shape of the tree as a whole.
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Stone fruit trees
Stone fruit trees include cherries and plums and other fruit trees that produce a hard pit (or stone) in the middle of their fruits. These kinds of fruit trees vary widely in their shapes and sizes. And this also applies to them as standards, half-standards and whips. Important in pruning is the proper distribution of the fruiting wood in the tree.
Stone fruit trees are very susceptible to gum disease and silver leaf. For this reason, these kinds of fruit trees are always pruned during late summer or early autumn. Because the wounds heal quicker during this period, pruning them then greatly reduces the chance of infection. But the best way to avoid problems with stone fruit trees is not to saw off any heavy branches.
This makes it even more important to start proper maintenance pruning right from the beginning. And if creating larger wounds cannot be avoided, apply a wound dressing.
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Plums
Plum trees are often purchased in tree or bush form. They should be pruned only moderately. Every year, their laterals lengthen and produce one-year-old shoots that should be shortened by 50% during late summer to early autumn.
As with any other pruning, you will also have to remove any branches that cross one another by eliminating just one of them. Keep the canopy nice and open to admit light and air in through the middle of the canopy.
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Sweet cherries
There are many different varieties and forms of sweet cherries, one being the May Duke. Although the use of special rootstocks is increasing the success of delaying the growth of these trees, sweet cherry trees usually become larger than plum trees, one reason for this (except for espaliered forms) being they are not heavily pruned.
Pruning focuses mainly on shaping, and young branches are thinned out during the summer to admit enough light in through the canopy. For espaliered forms, the young lateral shoots are headed to up to seven leaves in the summer and again in the summer to 3 to 4 buds.
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Sour cherries (morellos)
Unlike sweet cherries, sour cherries bear fruit only on one-year-old wood (on the shoots or twigs formed the year before). Only the leader on such a shoot is a leaf bud that produces only leaves and from which the next shoot (a branch by that time) will continue to grow.
Since such an extension can be flowerless, it should be pruned back (also done during the summer) to the lateral shoots that grow from it and that will produce flower buds and then fruit. With sour cherries, too, be sure to consider the shape of the tree as you prune.
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Peaches and nectarines
Peaches and their closely related nectarines are often trained as espaliered trees (e.g. a fan shape) or maintained as a shrub. Peaches bear fruit only on wood older than one year and then only once per branch.
This means that new fruiting wood has to be available every year. And this means that new shoots that will bear fruit have to be given the opportunity to develop and that spent branches will have to be removed.
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Soft fruit
Grapes
Grapes and kiwis have to be pruned before February 1 because these soft fruits build up an enormous sap pressure very early in the spring. If you prune them too late, the plants can start bleeding heavily. Since the sap will literally spray from the vine, the wound will be unable to heal (with very adverse repercussions).
When pruning, remove all of last year’s shoots that developed from the lateral vines up to one to three buds. New shoots will be produced from each stump from which (ultimately) only one flowering shoot will be kept. This one will be topped back, starting at the flower cluster, to three to five leaves.
From here on, new shoots will regularly emerge from the axils and will have to be removed. The grape clusters ripen somewhat faster if there are no leaves shading them.
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Blueberries
These shrub-shaped berry-producing plants require acid soil. Some varieties can reach a height of 2 metres. Usually, four to five laterals per shrub are retained and will not be shortened during the first two years. It is on these laterals that the shrub forms fruit-bearing shoots.
Because these fruits are produced only on one-year-old wood, the spent wood will have to be removed on a regular basis (replacement pruning) starting in the third year.
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Red and white currants
These shrubs need no support of any kind and can even be used as a hedge. Actually, letting them grow without support is the most common way of cultivating them. This method calls for retaining four to five stems. If trained onto a trellis, three stems are usually retained.
The stems are pruned every year. Once they have reached the desired height, they are trimmed back to a strong lateral shoot. Appearing on the stems will be lateral shoots that will produce berries. These are either pruned to a longer length (that will produce many small berries) or to a shorter length (that will produce fewer but larger berries.). This is usually done in late January.
The clusters of fruit ripen more slowly inside the shrub; this situation can be improved by pruning away the tips of the shoots during the summer, but remember to ensure that that at least six leaves are left.
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Black currants
These shrubs are only grown as free-standing shrubs. The nicest fruit clusters are produced on one-year-old wood (the wood formed during the previous year). Three and four-year-old stems bear less profusely. This is why replacement pruning is started during the second year.
Retain four to five stems. Regularly let the three-year-old stems be replaced by new basal shoots. Do not partially cut back the stems. You have to prevent the growth of branched stems (forks). Also prune away fruiting stems that are too short. Replacement pruning is carried out on black currents during the summer (after harvesting). The plants will produce more than enough new basal shoots every year.
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Summer-bearing raspberries
Summer-bearing raspberries bear fruit on the basal shoots formed during the previous year. Plant new plants and prune them to knee height in the autumn. This encourages the formation of new canes that will emerge the next spring. Of these, retain up to eight to twelve canes per metre. Tie them to a trellis (composed of a few support wires one over the other) after the leaves drop.
Next year, top these canes to 10 cm. above the highest support wire. After harvesting, trim off the spent canes (these will die after harvesting anyway). In the meantime, new canes have already developed with which you can repeat the entire cycle.
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Autumn-bearing raspberries
These raspberry varieties bear fruit after the summer on canes that were formed in the same year. Prune all canes way back in the autumn after harvesting. Next spring, retain ten to twelve new canes and tie them to the trellis. Autumn-bearing raspberry plants are not as robust as summer-bearing raspberry plants.
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Japanese Wineberries
This plant produces climbing canes that can be handled in about the same way as summer-bearing raspberries. It produces fruit on canes formed the previous year. After harvesting, the spent canes partially die back. It would be best to cut these off and let them be replaced by new basal shoots that have emerged already.
You could also let the plant climb upward several metres against a trellis and then limit your pruning to the parts that die off.
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Gooseberries
Gooseberries bear on one-year-old wood. In December, thin out all branches that are too short or too thin. Any basal shoots that will not be used to replace spent branches are also removed. Gooseberry hedges grown on a support wire are usually pruned back to a height of 40 cm. Twigs and branches hanging too closely to the ground are also cut away.
Sometimes, overly dense shrubs will need to be pruned here and there in the summer to admit more air. Always remove any parts of the plant affected by fungi as soon as you notice this.
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Blackberries
These partially climbing fruit-bearing shrubs produce fruits on one-year-old canes (basal shoots that emerged during the previous year). New canes will shoot up during the summer. Tie these to support wires so that they bend outwards.
As soon as the canes grow very far above the top wire, they should be topped to a height 10 cm. above it. These main canes will produce laterals on which the berries are born. Spent canes should be pruned away during the spring.
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Other berries such as loganberries, tay berries, etc.
These brambles are usually hybrids created by crossing blackberries and raspberries and also display the characteristics of one or both to a greater or lesser degree. This means that they must be pruned using the same methods as used for raspberries or blackberries.
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