My magnolia tree is wilting. It has stunted growth, the leaves are no longer shiny and bright. They are turning yellow and brown and falling. The clusters of leaves are hanging (reminds me of how grape clusters or wisteria flowers hang). I have read of a desease in the soil called I believe, Verticulum Wilt?? The fight against it was said to, apply a very high nitrogen fertilizer to the soil and then blanket the ground surrounding the tree with a clear heavy plastic for 6 weeks. It is supposed to cook the soil and kill the bacteria that is stopping the tree from absorbing the water it needs. The tree is showing alot of new leaves emerging but very few blooms. Any sugguestions?? Thank you