Crepe myrtle shedding leaves
I have a crepe myrtle, white blossom variety and it seems distressed. It blooms in late summer, and for the last two years the blooms have been sparse. Late this spring it began to shed its leaves. I cannot see any evidence of pests or fungal disease. The twig that supports the leaves has turned reddish in color and the leaves are slightly rumpled rather smooth in appearance. They detach from the branches at a slight touch. Is there some plant disease at work, or is the tree declining due to lack of water or nutrients. I am located in North Ocean City, MD, and I read that crepe myrtle does not tolerate sea shore climate very well.
I have a pink variety of the tree and it has been vigorous and healthy except last year it too had fewer blooms than usual. Both trees were planted as saplings over ten years ago. The healthier one is planted next to a drainage control garden.
Worcester County Maryland
We see no disease or insect issues, which point to an environmental/cultural problem--known as an abiotic problem.
We can't see any flare on these trees. The flare is where the trunks widen as they go into the ground. Trunks should not go in straight like a lollipop. When trees are planted, or become, too deep they actually as smothered because the roots cannot get enough oxygen (or water) and they slowly die. We suspect that so much gravel (or mulch or soil) has been added around the base of these trees that it is possibly burying the roots.
Here's more about several abiotic issues, including "planted too deeply": https://extension.umd.edu/hgic/topics/tree-and-shrub-problems-not-caused-disease-or-insects-abiotic
We see that the shrubs to the right in the first photo are also not doing well. We wonder if a herbicide is being used to keep weeds down in the gravel. Many herbicides will travel down into the soil and kill the roots underneath of nearby trees and shrubs. Keep in mind that the roots of a tree can reach out as much as 1 1/2 times the height of the tree. Read the label of any herbicide you use very carefully. Dicamba is one ingredient that will do this.
Stones actually retain moisture in the soil more than mulch. With all the rain the past 2-3 years, it's possible that the crape myrtles got too much moisture at some point, depending upon whether you have a clay soil or not.