I live in Richmond. I have an eleven year old weeping willow that has lost a lot of its leaves. It has been extremely healthy and beautiful for the past ten years. What has happened and is there anything that I can do to help it?
It's not unusual for weeping willow trees to shed leaves if they are under stress. There are several things you can look for to see if any apply to your tree.
First, is there a "root flare" showing above ground level? That means the trunk flares out just before it goes into the ground, not straight like a telephone pole. If there is no flare, the tree was probably planted too deeply and there may be issues with rotting of the bark and vascular areas below the ground level.
Secondly, is the tree in an area where it gets enough water? These require ample moisture in the soil. One way to assure this condition is to mulch the area under the drip line of the tree. That is, all the way to the edge of the widest limbs of the tree. Don't pile the mulch up around the base of the tree (mulch volcanoes) like you see in parking lots and other landscaped areas. This can cause rot of the bark similar to what happens if the tree is planted too deeply. Water the tree when the weather gets drier, slow deep watering with drip hoses is best or a sprinkler that waters once or twice a week, making sure the water penetrates at least 6 to 8 inches into the soil.
Have you noticed any insects or damage to the leaves? Gypsy moths can be a problem with these trees and cause leaf loss. There are other insects and diseases that can cause problems with weeping willows as well.
The best advice I can give you is to call a certified arborist to take a look at the tree and provide a diagnosis of the issue as well as let you know what, if anything, needs to be done about the problem. I'm certain this is a valuable and highly decorative tree in your landscape and preventative measures may save it so it gives pleasure for many years to come. A list of certified arborists that work in our area can be found here.
Good luck with your tree. If you have additional questions on this subject, please use the reply feature within this email or call the Chesterfield County Cooperative Extension Office at 804-751-4401. And thanks for using Ask an Expert!