SOME TREE CONCERNS FOR FALL

QUESTION: An oak tree that is growing in the middle of my patio has dead branches under the living canopy and some leaves are falling. The tree is quite large with a trunk diameter of over two feet. Natural rainfall is the only water it receives. The patio was built two years ago. Why is this happening? Don't oaks stay green year around?

ANSWER: The oak tree is a very large and old specimen. An oak that has a diameter of over two feet must be at least 100 to 150 years old. The dead branches are those that are under the living ones. When new growth occurs older branches can be shaded out and not produce leaves; they have served their function and die. Prune out the dead branches to make the tree more sightly. Leaves of evergreens do not live forever but don't fall all at once. During certain times of the year it is natural for some evergreen leaves to die and fall. By placing a patio around the tree perhaps some of the roots do not have the access they once did to rainfall. However, it must be remembered that mature trees normally have actively feeding roots only 40 to 60% of the distance in from the drip line towards the trunk.

QUESTION: I have Chinese elm trees that are infested with elm leaf beetles larvae and mulberry trees that have the mulberry tussock moth larva on them. What can I do to get rid of them?

ANSWER: The leaves of these deciduous trees will be falling soon and these insects have or will begin over-wintering. There is no reason to try and control them now because they are already "hibernating". These insects will reappear next spring and that is the time to control them. Let the leaves fall and put them in your compost pile for use in the spring.

QUESTION: When should I prune my fruit trees and roses?

ANSWER: Pruning of fruit trees should be done when trees are dormant, after rest is completed in the winter. Rest is a physiological stage where tree buds cannot be forced to grow even under ideal growing conditions. Generally rest is completed after Christmas. Pruning can begin in January and continue through bloom in the spring. However, dead or diseased limbs and root sucker growth can be removed at any time.

Roses that bloom several times during the year should be dormant pruned during late winter or early spring before new growth begins. Roses that bloom only once during the year are pruned after flowering; normally late spring or summer.