I planted three Sienna Glen Maples 2 plus years ago so this is their second full summer and fall in my yard. They seem to be healthy and have grown nicely, but the fall colors are short lived and disappointing. They turn a light brown and then yellow and fall all within about 10 days, the trees are about 2/3 bare now. Location is central Wisconsin and sandy soil. Not sure if this is normal or I need to fertilize etc.