About three quarters of the leaves on my plum tree have fallen off. I don't think its time for that yet? There is new growth popping up on all the tips of the branches. The dead leaves turn Brown on the tips, then around the edges, then little silver spots started occurring in those brown areas, then the leaves fall off. I DID forget to water one week. Does anybody think this might be a disease, or just a lack of hydration issue? Houston area.