The eastern cottonwood tree or populus deltoids is a fast growing, short-lived deciduous tree, deriving its name from the many cottony seeds that it sends out June through July. The eastern cottonwood can reach a height of 75 to 100 feet. This is a high-maintenance tree due to the dropping of leaves, fruits, flowers, branches and twigs. Prune eastern cottonwood for these reasons: to remove dead, diseased, or damaged branches, to maintain size within in your landscape, to keep branches away from structures, roofs, and walkways and to thin out the crown of the tree.
Cut off any damaged or diseased branch as soon as possible. Make a clean cut at the breaking point or by cutting off the entire branch or limb. Be sure to make a clean cut so that the wound can heal properly. You can and should prune dead or diseased branches at any time of the year.
View your tree from all angles, and locate the branches that need to be pruned to maintain size or to insure safety. Determine where the branch collar (located on the underside of the branch where it connects to the trunk) and the branch bark ridge (located on the topside of the branch where it connects to the trunk) are located on the branch you are going to prune.
Make a clean cut in front of the branch bark ridge and the branch collar; do not leave a stub. Also take care not to cut into the branch collar or the branch bark ridge. This area should be maintained for the integrity and health of the tree. Pruning should be done when the tree is dormant, which is in winter or early spring.
Examine the crown of the tree to determine if you need to remove deadwood (dead twigs, branches, or limbs) from the crown of the tree. This is called "thinning" of the crown. Due to the heights involved it is generally done by a professional tree service. A certified arborist will be on site to determine what branches to thin out to maintain the appearance, health and integrity of the tree.