The size of an apple tree is best controlled by planting the appropriate rootstock for the size of tree desired. Rootstocks that produce small and dwarf trees are available. Soil fertility also affects growth.
Trees that were planted too close together or that are too large for the landscape may be controlled by careful pruning. Scoring, ringing and root pruning are more drastic measures and require the orchardist to be careful, but they are effective in controlling growth.
Prune apple trees while they are dormant to thin out the growth and to head off branches that are growing too tall or in the wrong direction.
Remove branches that restrict light to the interior of the tree. Use a handsaw or loppers to thin out the vegetation inside the tree and thus allow better light penetration.
Remove branches growing vertically to control height. Limbs growing mostly up or down should be removed. Leave limbs that are growing horizontally with a slightly upward tilt.
Prune the top of the tree back to a weak branch on the central trunk. Pruning the top encourages growth in lower sections of the tree and maintains the desired tree height.
Scoring or Ringing
Ring or score the tree in the spring when the new growth is about 4 to 6 inches long. Ringing is more drastic than scoring and should be done with care only when an extreme reduction in growth is needed.
Score the bark of the apple tree by making a continuous cut completely around the trunk with a sharp knife.
Ring the tree by removing a ring of bark instead of just scoring it. Make two cuts each going half way around the tree. Make the second cut about 10 inches higher than the first, and overlap the ends of the cuts by about 2 inches. Use a pruning saw or ringing knife to remove a ring of bark approximately 1/16 to 1/4 inch wide.
Time root pruning to occur some time after the tree blooms until about 10 days after the petals fall. Pruning too late in the season has less benefit and increases fruit drop.
Attach a sharpened subsoiling blade to the tool bar of the tractor. Set the blade to a depth of 12 inches. Cut through the soil approximately 36 to 40 inches from the trunk on both sides of the tree.
Repeat the root pruning one month later if needed.
About this Author
Diane Watkins has been writing since 1984, with experience in newspaper, newsletter and web content. She writes two electronic newsletters and content around the web. Watkins has a Bachelor of Science degree in chemistry from Clemson University. She has taken graduate courses in biochemistry and education.