Can excessive water kill a magnolia tree? I know they like a soil with a PH of 5 but after watering the sod under the tree with well water for many weeks, the PH is now 7. The installer of the sod said the sod had to be so wet that when we stepped on it the water would run over the top of our shoe. When we expressed concern when the tree started showing stress he said it wouldn't hurt it and to keep watering. This tree is 60 years old and just beautiful. Every spring the whole tree is filled with huge pink blooms and it was nice and green until the watering continued. It is now brown and the leaves are mostly all gone. Could the water have done this.