What can you do for an apple tree that is getting too much water?
Thank you for contacting us. Most trees require good drainage. If you have only one tree that has poorly drained soil, you should see if there are any downspouts or other sources of water that can be rerouted. If water is draining towards the tree on the surface of the ground, cut a very shallow mote (no more than a couple of inches deep) around the dripline and try to route the flow around the tree.
The real issue may be soil that does not drain properly. This requires a longer term solution to improve the tilth of the soil. Organic matter, such as mature compost, well-rotted manures or chopped leaves, should be spread across the entire root zone of each tree twice a year. This should be an inch thick, and keep in well-away from the trunk of the tree. Do not till it into the soil, but you may rake into the surface if desired.
An added measure would be to top off the compost with two to three inches of organic mulch, if possible. Mulches will eventually break down providing additional organic material to the soil.
Building healthy soil is your best practice for health plants that can endure adverse weather conditions and pests. Here is a good article on this topic: http://www.rodalesorganiclife.com/garden/feeding-healthy-soil