The Rockdale Gardener

Gardening Posts From Rockdale Cooperative Extension

Training Tomorrow’s Leaders: Training Leaders in Shade Trees

leader perfect

This tree has a single leader. In shade trees, this gives the tree strong structure and superior wind resistance.

After graduating from the University of Georgia with my undergraduate degree in horticulture I went to work on a farm. It was an ornamental in-ground tree farm to be exact. The farm was Mid Georgia Nursery, Inc. located in Meansville Georgia, a thriving metropolis of less than 400 people.

We grew trees for the wholesale landscape trade in fields in rows much like an orchard. When they achieved the proper size, they were marketed and sold. We dug the trees using tree spades (hydraulic implements mounted to the front of skid-steer tractors), wrapped the rootball with burlap, set in it in a basket and shipped to as far away as Chicago. It was a great job and I loved working outdoors.

While employed at the farm as the Production Manager, I learned a great deal about producing high quality trees and shrubs. Under the tutelage of the farm manager Mr. Phil Hart, I learned one of horticulture’s most difficult skills, the art of pruning (Phil had managed the farm for a decade or so and his former job was pruning manager at the famous Princeton Nursery, the birthplace of the ‘October Glory’ TM Red Maple). Phil was terrific to work for and a great horticultural mentor.

leader double

This tree has a double leader. The leader to the left should be removed. Double leaders are inherently structurally weak and can split during wind events.

One of the tricks he taught me was the concept of training a single leader in a shade tree. An ideal young shade tree specimen should have a single straight trunk from the roots to the very uppermost bud. When the tree is too tall to prune then it is allowed to form the rounded multi stemmed canopy we are familiar with in mature shade trees.

Trees grow at the branch tips where the apical bud, the leader as it were, suppresses other buds behind it. The apical bud produces auxin, a plant growth regulator. This chemical allows the bud to maintain its position as leader by reducing the growth of its competitors. Remove this apical bud and the chemical is gone and all of the other buds are released beginning a mad dash try to assume the leader’s former role. This results in bushy growth with one or more branches that are equals. These equal branches compete for resources and space. Eventually they can create weak spots in the trunk leading to the tree splitting.

pruning horrible 3

Do not ‘top’ trees! ‘Topping’ is a term for the removal of the majority of the canopy of a tree. This procedure ruins the structural integrity of the tree and invites pests.

The point is to aid a single leader to maintain its position in the canopy of the tree. Tree owners can do this by pruning out any competing leaders up to a certain height. This type of pruning may be done throughout the summer. Use a pole saw (watch out for power lines!) and prune the other branches at least six inches behind the desired leader. A stub of one of the removed branches can be left and the single leader may straightened and taped to this stub with masking tape. The masking tape will last long enough to correct the leader’s growth but will rot soon enough to prevent future damage.

Some trees need more attention than others. Maples are notorious for wanting to form big round canopies at three feet from the ground. Oaks tend to want to form single leaders. Keep a close eye on your young shade trees to maintain single leaders. If you are unsure of how to do this type of pruning consider hiring a professional arborist.