Fruit tree pruning is both an art and a science. The art to fruit tree pruning is not something that can be taught in a short article or video, but basic pruning technique is quite easy to understand, and once grasped, almost anyone can maintain a fruit tree, and do so successfully, year after year.
This article explains the technique of fruit tree maintenance pruning or detail pruning in it’s most simplified form. In the following sections, we’ll learn how to make pruning cut, and what to cut, to keep a tree to a manageable size and consistently fruiting.
NOTE: Care must be taken when making pruning cuts to remove branches, for more information please see the article – Tree Pruning, How to Remove Tree Branches Correctly
NOTE: This article assumes that the tree to be pruned has an established form and structure, basically it has branches and shaped either a vase or central leader form. For new trees less than three years old that need to be shaped, please see the article – Framework Pruning, Shaping Young Fruit Trees in the First Three Years (coming next week).
Pruning a fruit tree involves three distinct steps, each serving a different purpose.
1. First Steps in Fruit Tree Pruning
Before any pruning cuts are made to a tree to make it smaller or change its shape, there are a few pruning steps which need to be carried out first:
- Remove any dead, diseased and broken branches.
- Eliminate crossing branches by pruning out one of the branches.
- Remove suckers, water sprouts and most competing branches growing straight up into the tree.
The purpose of removing diseased branches is for the purposes of good plant hygiene, to prevent diseases spreading further and killing the tree, or infecting other trees.
When branches rub against each other, the bark gets stripped away at the point of contact, creating a wound that can serve as an entry point for pests and diseases, as can broken branches. Trees are better able to seal off wounds and heal over when clean pruning cuts are made.
Suckers arising from the rootstock of grafted fruit trees must be removed, or they will sap a tree of its vitality. Being very vigorous, the suckers will overgrow the original tree, often causing the main graft to die off. The rootstock suckers are never the same variety as the graft, so they are not productive varieties, and are therefore inedible. Rootstock varieties in grafted fruit trees are to either reduce the trees size or because they impart other properties, such as handling particular soil types.
Suckers arising from the soil can be cut off at soil level, while any coming from the stem can simply be rubbed off with a push of the finger when they first form as buds or soft green shoots, or pruned off if they are older.
Water spouts, also known as water shoots, are overly-vigorous new shoots that grow at an alarming rate vertically straight up towards the sky. They are easy to identify as they stand out from the rest of the tree’s usual growth. If left unpruned, water shoots will grow to become an extension of the main trunk of the tree, and ruin the tree shape. Prune out water sprouts completely or cut them back to a few buds to use then to create new growth.
2. Pruning to Maintain Tree Shape
Fruit trees are trained into various shapes, such as a vase, standard leader, espalier. etc. Once trained into a chosen form, the tree shape needs to be maintained.
The next step of pruning involves removing competing branches that disrupt the trees shape:
- Remove inwardly growing branches on a tree pruned to a vase shape
- Remove additional leaders growing on a central leader shaped tree.
It’s important to keep the centre of a vase-pruned tree fairly open to allow light in for more even fruit ripening, and to reduce the likelihood of fungal diseases which result from poor air circulation when leaves stay wet overnight.
Maintaining a single leader on a central leader shaped tree is critical for easy maintenance.
3. Pruning to Renew Fruiting Wood and Maintain Tree Size
Once all the damaged wood is removed and competing branches are cleaned up to preserve the tree’s shape, then the third step is to prune the branches to renew the fruiting wood, and reduce the size of the tree to make it more manageable when spraying, netting and harvesting.
- The simple rule for pruning fruit trees is to cut back all new growth back by half, to an outward-facing bud, making the cut at a 45-degree angle, and 6mm (1/4”) above the outward-facing bud.
Depending on the length of the new growth, it can be cut back by as little as one-third, or as much as two-thirds to the fruiting branches back to a manageable length.
Why prune at all? When fruit trees are not pruned, many display a pattern of biennial cropping, where they produce lots of very small fruit one year, and almost no fruit in the following year, to prevent them exhausting their energy reserves.
If the fruit is thinned out when it is just beginning to form, a tree can direct its available energy reserves into far fewer fruit, which allows the remaining fruit to grow much larger, and be of higher quality. Having plenty of energy reserve left over, a tree can then produce a similar crop in the following year too.
The practise of fruit thinning, cutting off individual fruit from the tree as they begin to form, is quite tedious and laborious, but there’s a much easier way to overcome biennial cropping! By pruning back new growth back to half its original length, future fruiting wood is reduced by half, which in effect reduces the fruit that will be produced by half, thereby thinning the fruit. Pruning also causes cut branches to shoot and produce more side branches, which renews and increases the fruiting wood for following years.
The reason for cutting above a bud at a 45-degree angle is so that the water runs off, away from the bud. If the bottom of the sloped cut directs water into the bud, it may cause it to rot.
The cut is made at a distance of 6mm (1/4”) above the bud (which is a little less than the thickness of a pencil, that’s 7mm thick) to give the branch room to heal above the bud. Cutting too close to the bud will cause the bud to dry out and die off.
The reason for cutting to an outward facing bud is to direct new growth outwards, away from the trunk of the tree. New branches grow from buds, and they grow in the direction the buds are pointing. If buds are pointing inwards, branches will grow into the tree, crossing into other branches and ruining the shape of the tree.
How should branches be cut if they’re not vertical? The whole point of angling the pruning cut is to direct water away from a bud, so if the branch is horizontal, make a vertical cut 6mm above a downward or sideways facing bud.
Cutting new growth in half to an outward, sideways or downward facing bud:
- Directs the growth outwards each year, away from the trunk of the tree.
- Thins the fruit, ensuring consistent cropping year after year.
- Keeps branches shorter to allow them to bear heavier crop loads without breaking.
- Regenerates the fruiting wood by inducing the growth of new branches.
Each cut branch will produce two or more branches, which are then cut to produce two or more branches, and so on, increasing the branching of the tree, and the potential fruiting-bearing wood.
Below is an illustration of how branches are shortened each year to an outward, sideways or downward facing bud, and how the growth extends a little further each year.
Only the growth of the leading bud is shown in this example for the sake of clarity, in reality, many of the buds would shoot to form new branches, and branching will progressively increase with each passing year.
Once branching extends out too far, the main branch can be headed back to a new leader by cutting back to a smaller branch to replace it, as shown in the picture on the right-hand side.
If branches bend downward too low beyond 90 degrees (below the horizontal level), they lose vigour and produce only a few small fruit. In such cases, the portion of the branch hanging down below the horizontal can be pruned off to renew the fruiting wood.
Trees with Special Pruning Requirements
Apricots should NOT be pruned in winter. Pruning cuts are made in cold, wet weather act as an entry point to diseases and apricots are particularly susceptible to gummosis, recognisable by a characteristic bleeding of orange sap.
Apricots can be pruned from late spring (after the cold wet weather has passed), all the way through to early autumn (just when trees begin to lose their leaves). Select a dry and preferably windy day, where no rain will fall the following day either, to allow pruning cuts to dry and seal off well, to prevent infections entering.
Some trees can’t just be pruned the regular way, by cutting off the ends of all new growth, because they either fruit from the terminal ends, or sprout shoots from the terminal ends which produce the fruit. Some fruit trees which need to be pruned differently are:
For more information on how to prune these fruit trees, please see article – Fruit Trees with Special Pruning Requirements – Figs, Persimmons and Pomegranates
That’s all that’s required to maintain deciduous fruit trees at a manageable size, and keep them productive. They’ll crop consistently if they’re pruned each winter, and fed with a balanced fertilizer at the start of spring and autumn.