When is it ok to prune an overgrown apple tree?

Question

I recently bought a new house and I'm trying to get the garden in order. It has an apple tree which has lots of low branches and appears generally neglected. Some of the leaves are silvery and look ill.

It blossomed in late May and, now in late June has started producing some pathetic looking fruit. Is it ok to start pruning now? If so, how much should I prune? Below is how the tree looked in May:

I'd like to at least remove the low branches and ideally the high branch coming in from the left. Should I wait until winter or is it safe to do now/summer without damaging the tree?

Answer 1

Summer is the time to remove vigorous growth and keep the tree to a manageable size. Winter is the time to structurally prune and to stimulate lots of new growth.

Say, for instance, you have a tree with 5 branches. In winter, the sap moves down out of the 5 branches. Then you cut 3 of the branches away. In spring, when the sap rises, it will be looking for those 3 branches, which aren't there, so the tree will send out lots of new growth. If, instead, you remove the branches in summer, you're removing the sap with the branch; therefore, won't stimulate as much vigorous growth next spring.

-When pruning, be sure to use clean tools. Apply bleach or some disinfectant to blades to kill fungi and bacteria.

-Be sure to cut correctly. Cut limbs to the collar, but not into it. Don't leave a stub to rot.

-Prune to a bud facing the direction you want a new limb to grow.

-Don't prune when rain is certain. Wet conditions are conducive to disease.

Also, with apple trees, its important to thin the fruit in the first 6 weeks of fruit formation or there won't be much fruit the following year. You should thin the fruit to 6 inches or so between apples.

Here is a video that will alleviate your fears of summer pruning fruit trees: http://www.youtube.com/watch?v=BZ6isBVPcpc

Another video concerning winter vs summer pruning: http://www.youtube.com/watch?v=WZQfbGlzz90

Some kinds of tree you don't want to cut on in certain months and in certain areas of the country (world). For instance I won't make cuts on pine trees when its warm enough for insects to be about for fear of the Southern Pine Borer, which could wipe out acres of pine trees. I hate to cut an oak in summer for fear of attracting insects. You should research the tree you want to prune and be aware of the insects in your area which could attack a wounded tree. Additionally, fruit trees are cheap and easy to replace. Large oak trees are not.

Answer 2

The first question is whether the tree is worth saving.

• is it located in a good position? Not too near the house, not where dropping fruit hits something like a car, where it gets good light.
• is it an apple tree or a crab apple tree? If you do not use crab apples and it would years of work to bring it back to a productive size then it may not be worth the work.
• does it have insects or disease present? If it does this does not mean you cannot rejuvenate it but it does mean more work.
• what reduction in height is required? If the tree is thirty feet tall you can bring it down to twenty feet in three years but then you are still using a ladder to harvest and prune and special equipment to spray
• are the main limbs structurally sound? If there are cracks in the limbs or the branches do not look like they will support a load of fruit then it may not be worth saving.

• are you prepared to invest the time? Typical yearly tasks are:

  - prune the tree in winter
  - spray with dormant oil in the spring
  - harvest in the fall
  - store your apples somewhere cool or dry or process them
  

You can buy a dwarf apple tree that will never get more than six or ten feet tall that crops a known variety and will probably be less work than trying to bring an overgrown tree down to a height you can work with.

If you still want to invest the time in your existing tree this is what you can do now in summer time:

• remove all sucker growth from the base of the tree by pulling not cutting. (cutting encourages regrowth)
• remove broken and crossing branches
• remove all other shrubs and trees that are competing for light and water

Late winter is the preferred time to start rejuvenation pruning. You can see the structure better and the tree is dormant so your cuts will not encourage sucker growth.

How to do rejuvenation pruning is another question but is covered in some detail here, here and here.

Edit: now I've seen the picture it does not look that overgrown. The location seems good but you should still wait to do pruning till late winter. If you prune now you will encourage growth that you will be cutting back later.

Edit: Rob wants to know if he should remove the low hanging branches. This depends on what your goal is. If you want to be able to harvest fruit without using a ladder you should work on removing the highest branches.

I agree with Randy that you can prune in mid summer but I don't see that the tree is so out of shape that you have to.