This week we’re talking about how to prune apple and pear trees. If you haven’t read our little introduction to the language of pruning fruit trees you can catch up here.
The first part of this post is about how to properly shape young apple and pear trees from the beginning. The second half is about how to prune older trees that may have been shaped differently or neglected for a few years, because lets face it, many of us have those in our gardens!
I recently spent a morning with my friend Dennis Cassidy, export grower and pip fruit industry leader. We wandered around his Nelson orchard and he taught me to prune apple and pear trees, the same way he teaches new recruits on his orchard. And he must know a thing or two because he has an average harvest of 180-200 kilos of fruit per tree!
First you learn the 4 parts of the tree, TRUNK, ARMS, BRANCHES and SPURS. Dennis recommends talking to yourself when you are pruning to remind yourself whereabouts on the tree you are – are you on an arm, branch, spur or trunk? – this will help you decide how you should prune it (all will become clear).
Setting a Framework for New Trees
Shaping a young tree properly will make pruning easy in future years and will increase the production of your tree. The most popular shape for apples and pears is known as a central leader, it is a single central trunk with side branches.
To select the arms for your tree, remove all branches coming off the trunk for the first meter to give you room to mow under the tree and so the weight of the crop won’t drag branches to the ground. Then select 4 or 5 branches growing straight out at even spacing around the trunk. If you’re looking down on the tree from above, you should see a cross.
Remove any other branches coming off the main trunk for a meter above these arms and keep the main trunk intact and growing upward. Most of your fruit will grow off these 4 or 5 lower arms.
Tie the 4 or 5 arms down with loops of twine to encourage them to grow straight out, not up. The loop lets the branch grow without being strangled and damaged by the string. Don’t tie them down too tight, so they point downwards, or their growth will slow. You want these arms to be growing straight out from the trunk or slightly upward. When tied, the tip of the branch should not be lower than it’s join to the trunk as they will lower over time with the weight of fruit.
Orchardists hammer a metal staple into the base of the trunk and anchor the ties to this which doesn’t seem to harm the tree. The ties are removed after a winter, and these bottom arms grow straight out for the remainder of the trees life. Here is a photo of a good set of arms on a 20 year old tree. They are about a meter off the ground and grow straight out, evenly spaced around the trunk.
Along each arm you let branches grow. Select branches that are growing straight out from the arms, not up or down. Allow at least a secateurs length between each branch. Secateurs are a handy ruler to use when pruning. Well spaced branches let the light and air around the crop as it ripens and prevents overlaps. You can see these branches growing off the arms in the photo above.
Where each arm joins the trunk, leave a little bit more than a secateurs length before the first branch, just to keep the arm clean of branches around the trunk.
Now you’ve got your arms and branches sorted, what do you do with the growth above them?
Shaping the top of the Tree
Let the central trunk keep growing up from the arms and allow a meter between the arms and the next branches coming off the central trunk. These upper branches are not called another layer of arms, they are branches. The difference between them and the lower arms is you don’t let branches grow on them. You keep pruning these upper branches back to spurs. This keeps them small and ensures the upper growth doesn’t shade the fruit development on the larger, lower arms.
Replace these upper branches every few years when they get too large and long, so that the vigor stays in the lower arms of the tree. A well-balanced tree should have a slight pyramid shape to it with wide lower arms and shorter upper branches. Here is a picture of mature trees with wider arms at the base and smaller branches drooping off the top of the trunk.
Shaped like this there is no need to cut the top out of the tree as it will naturally lose vigour as the crop on the lower growth takes the energy from the top of the tree. There is no need to cut the top out of the tree as it will naturally run out of growth at around 3-4 meters. Cropping is a more effective growth management tool than pruning. Pruning just encourages growth so you want to minimise the pruning you do.
Managing Growth on Branches
Once you have your framework, you need to prune back to this each year to keep your tree open and productive. The first and most important rule is – do not grow branches on branches. Only fruiting spurs should grow on branches. If you let branches grow on branches, your tree will get clogged up, lose light and room for fruiting spurs.
This is when reminding yourself what part of the tree you are on comes in handy. Am I on an arm or a branch? If I’m on a branch I need to remove any branches starting to grow from it. A branch on a branch is easy to spot as it sticks up and has a faster growth rate than a spur. You want your branches full of spurs, not branches. Here is a photo of branches on branches being pruned off.
Branches on arms and on the upper trunk also need to be replaced every few years when they get too large. So look for replacement branches while you are pruning. These replacements can be tucked under an existing old branch to get them growing in the right direction before the older branch is removed the following season. Select replacement branches that will grow straight out from the arm and tuck them as straight as possible from the arm.
The final note about branches – is don’t tip them unless they are coming off lower arms and get below knee height. Just let a branch grow out. Tipping branches just creates more pruning. Remember branches get replaced when they get too long or thick so don’t bother tipping them.
Growing and Pruning Spurs
The final part of our tree are the SPURS. These are short stumpy clusters of fruiting buds that grow on branches. Each bud can produce up to 5 fruit. They are the only things you want growing on branches, remember no branches on branches. Spurs are long lived but the longer and denser they get the more fruit they produce. An old set of spurs can easily have upwards of 100 fruit buds, which is far too many for the branch and if left, will create a heavy crop of small fruit.
You should aim to prune your spurs by 50% each year, either by shortening or removing them. This will reduce the amount of fruit thinning you have to do in spring and improve the quality of your crop. Remove any spurs that are longer than your secateurs, shorten and thin the rest. Remove any that are growing underneath the branch and try and keep spurs coming straight out along the branch. Here is a photo of pruning spurs.
When to Prune
The best time to do this pruning is after harvest when the new growth is still soft and can be snapped off easily with hands. This doesn’t damage the tree and there are fewer risks of fungal diseases in the dry later summer weather. You can also do the pruning in winter when the tree is dormant. Just be sure to use an anti-fungal pruning paste on all cuts.
Pruning Existing Trees
If like most of us, you don’t happen to have a tree with nicely formed arms, trunks and branches, all is not lost. You can still apply these pruning principles to get improved cropping and quality from your apples and pears.
I spent time with my friend Michelle recently pruning some old apple trees planted by a previous owner at her place. The trees produce a good crop and have been pruned over the years, but not to a central leader framework. So we went through and trimmed and removed old spurs, removed dead wood and overlapping branches, thinned branches along the main framework and tucked some replacement branches.
We didn’t have a classic central leader tree with lower arms and upper branches to work to, but the pruning we did will produce the same results. This is an older tree that produces beautiful apples each year and with the little bit of thinning we did it will put on some new growth and continue to.
If you’re dealing with trees that haven’t been pruned for several years, a hard pruning will produce a lot of new growth the following season but if you deal to this, the tree will settle back in, to a normal growth pattern the following season.
If you want to lower an apple or pear tree, do so in winter and paint the cut trunk and branches with pruning paint to seal the cut from infections. New growth will come away from around the cut and you can choose what to keep as replacement branches and what to remove.
Vase Shaped Apple & Pear Trees
You will quite often find apple and pear trees in older orchards that have been pruned into a vase shape rather than a central leader. This was popular but has been abandoned in favour of the higher production of the central leader shaped tree.
Here is a photo of an old Granny Smith apple tree on a property near mine, that has been pruned into a vase shape.
You can use the same principles when pruning an old vase shaped tree. Think of the upright scaffolding of the vase like the arms and the laterals coming off them as branches and use the same principles as above.
This tree hasn’t had last season’s growth pruned from it yet and you can see all the whippy branches that need removing to take the tree back to it’s framework.
There are few differences between pruning apple and pear trees. Different varieties of pears and apples have different growth habits but the same rules of pruning apply.
Your trees may also benefit from an application of nitrogen based fertiliser in autumn for the first few years until they are established. Once established there is no need to keep feeding them. Applying fertiliser in spring leads to a lot of leaf growth rather than fruit development.
Nashi pears are pruned in the same way but, depending on their root stock they do tend to send up vigorous branch growth each year. You may also prefer to only have lower arms and not continue with the central leader as nashi are hard to harvest without damaging the fruit – so if you can pick the crop from the ground, so much the better.
One final gem I collected from my visit with Dennis which is good to share – never prune fruit trees if washing wouldn’t dry on the clothes line. Fruit tree diseases, like canker and blight, love spreading their spores in damp weather so always prune on a clear, fine day.