The following tips will assist in the survival of newly planted and established trees.
Place mulch 3-4 inches deep around the base of the trees. This will retain moisture and prevent weeds and grass from growing around the base of the tree.
Do not build a cone of mulch around the trunk base of trees. This practice encourages insects and disease to attack the tree. It also causes root growth within the mulch resulting in poor tree stability.
Water newly planted trees. Regularly water new trees during dry periods for the first two to three years of life. Soak the ground thoroughly with a slow dripping hose. Established trees benefit from this practice also.
Do not over-water new trees planted in heavy clay soils. Trees can wilt and die if roots are sitting in water.
Prune. Cut off dead branches that cross or rub together, and suckers growing from the bottom and sides of the main trunk. (Oak trees should be pruned before April 1 or after November 1 to avoid oak wilt). Pruning cuts should be made close to the base of a branch (about ¼" away), do not leave a stub. Make cuts outside the branch ridge and collar; do not cut into the trunk of a tree.
Avoid nicking the bark on trees with lawnmowers weed whips. Diseases enter through wounds on trunks and branches may inhibit water uptake.