I am having problems with a Spanish style moss, which is round in shape, covering the end of the tree branches. It seems like whatever this is, it spreads from tree to tree by wind. A neighbor's tree is so heavily covered that it looks like it is being smothered and will not bloom. Have you ever heard of or seen anything like this and what, if anything, can be done to remedy this? This sounds like a ball moss which is an epiphytic plant, like spanish moss, that attaches itself to a host for support. It can interfere with photosynthesis if it gets to heavy and can weaken the tree. I would remove the moss by hand to help ensure the tree gets plenty of sunshine and air circulation. You can have the tree sprayed with a fungicide treatment that is specialized for this type of moss.