Q: We have a weeping willow tree that over the past 2 years has gotten more and more dead limbs. This year 1 whole side of the tree seems dead. I didn't think anything killed a willow.

Any ideas? It doesn't seem to have any insect borers or obvious diseases except dead branches.

A: You don't say how old or large this willow is, and it's possible that it may be dying from old age.

Otherwise, from your description, it is possible the willow has developed girdling roots that have strangled the tree, at least in part. Look for a root or roots that grow either around the base of the trunk or over the top of a root buttress at the base of the trunk.

If you do not see anything like this, look to see if the trunk has a flat side or sides, which can indicate a girdling root that is below grade, out of sight, but still encircling the trunk and choking it. You may need to excavate to find this out, so be prepared to get a little dirty.

If you find a root that is encircling the trunk or growing on top of another root, you might be able to sever it to relieve the pressure. If so, cleanly cut 2 ends of the root and try to remove it.

Be careful when cutting the root as there is often a lot of pressure on it and it'll pop out at you, sometimes flinging dirt into your eyes (I speak, unfortunately from experience).

If it is a large tree, you may want to call in an arborist to check out the situation and offer advice. He or she may then be able to perform the needed work as well.