Question
I planted a norwegian maple ( 7' tall ) three years ago in my zoysia yard and the tree has not grown at all. When the leaves come out in the spring it tops short of the upper foot of the tree so it is actually getting shorter.  I have fertilzed the tree each year several times and I have watered the tree adequately each week taking care to not to over water.  Is the zoysia grass presenting the problem?

Answer
The grass should not bother the growth of the maple unless you are using one of the Weed and feed type granular fertilizes on the grass--this Weed and Feed contains a herbicide that can kill or stunt the tree. It sounds more like you may have clay soil and when the tree was planted the hole was not large enough to allow the roots to expand outward. Normally the hole should be 2 times the width of the root ball as as deep. and filled with good top soil. Can not do msuh about that now.  Try taking a long screw driver and pushing it down near the tree and then go away from the tree at 6 inch intervals and see if the soil is hard. If so you may try loosing the soil around the tree where it is hard this should allow the roots to expand. The root system can only support (water and food) so much foliage and if the roots can not grow the foliage will not either.