Wood Water Garden

I can't hide it any longer. My lovely shishigasira lion's head maple tree has died. Only the lower branches came back last year after a very cold and very wet winter, and this year those few branches didn't make it either. I had to admit it. The lovely five-foot tree was gone. What happened? It was planted in a lower spot where a cottonwood stump had been removed, and it was surrounded by hardy ground cover. That meant that the pounds and pounds of snow that covered the roots just stayed there and flooded it with too much water in spring.  I read much later that the lion's head maple doesn't like it's feet to be kept wet. I have the old photos of it, but now realize I planted it in the wrong place. It should also have had more sun.   How many of you have had better success with these trees?