Losing Leafes in the Summer

Asked July 9, 2019, 1:09 PM EDT

I believe I have a Mature Dogwood? tree in my front lawn. For the last two years ( half ) of the tree starts to lose it's leaves in Mid July. Before it loses it's leaves they turn yellow. I can't see any spots on the leaves, and there hasn't been any underground work done in this area. It is located near a flower bed that is watered once a week.

Washington County Oregon

1 Response

If falling leaves are well distributed throughout the tree and result in a general thinning of the leaves, the problem is not serious. Trees will often set more leaves in the spring than they can support during the summer. Heat and drought stress will cause the tree to lose leaves that it cannot support with the available soil moisture. Leaves that drop are most often yellow with no discernible disease spots. However, at times, we can have green leaves drop that appear perfectly healthy. As long as the leaf drop results in a gradual thinning of the leaves, the tree should be fine if it is kept watered during dry periods.

Healthy dogwoods usually result from regular maintenance programs. Watering, fertilizing, pruning, and mulching are vital components of a good maintenance program.

In the absence of regular rainfall, dogwoods will need supplemental water during the summer and fall. Watering once a week, in the morning, with a soaker hose is recommended for their shallow root systems. The soil should be watered to a depth of 6 inches. Watering with a sprinkler is not recommended because it wets the foliage, creating ideal conditions for certain diseases.

Dogwoods in natural areas usually do not require fertilization. However, trees in yards and restricted growing sites can benefit from a suitable fertilizer. Soil testing is recommended to determine fertility levels and application rates. Broadcast fertilizer on top of the soil. Fertilize trees in late spring or early summer after leaves complete expansion. Never use fertilizers containing weed killer, always thoroughly water the area after fertilization.

Regular pruning serves many purposes. Removing dead and diseased branches helps prevent the spread of disease and insect pests, Pruning improves the tree’s structure as well as its appearance, with a few exceptions, winter is an excellent time to prune your tree.

Good luck and happy gardening.