I have a weeping willow tree that is very mature in my back yard. Last year, I trimmed it away from the house and it seemed to survive okay last summer and fall with new growth, and plenty of green. This year, about half the tree seems almost dead. I broke a number of dead branches off with my extension pole, and I need to know if the tree got infested with something and is dyeing or what else I can do to save it. Currently I put a fertilizer stake in the ground right near it and I also have made a tree ring and water it heavily each day. This tree has never had a lot of water, so it is not our dry climate that got to it. Any help will be appreciated.