I have an Ash tree that is next to a swimming pool. It loses its leaves before any other tree we have and causes us to shut down our pool earlier than we would like. Some of the leaves that have fallen don't look healthy. Is there anything I could do in the future to delay the falling of the leaves by a couple weeks? I have never sprayed or fertilized the tree and was wondering if this might give it a little more time? It is about 25 feet tall and has a trunk of about 12 inches.