We are in Florida. We bought a Mulberry tree a year ago in September. We kept it in the pot too long, and it started to drop leaves. We finally planted it. Then, soon after, a storm knocked it sideways. We put supports on it. That was winter. No leaves at all. We asked a tree service if it would live. They said it was dead. We didn't give up on it, so in the spring, it came back. It had lots of healthy leaves. Then, a few months ago (June), some leaves started with dark areas and then turned yellow and dropped. Now it has about 8 branches with 8 sickly leaves each. One branch with new, green healthy leaves. We noticed last week that the grass at the base was dead and yellow in a perfect circle. Do you know what caused this? We do have a neighbor who "takes care" of our plants sometimes without permission. He has removed lots of elderberry and firebush thinking they were weeds. I'm wondering if he tried to fertilize it?