I am very new to planting anything and have some questions. I have 10 4ft white pines, my soil is clay... I was told to use gypsum(sp) in the whole to help break up the soil because white pines do not like clay. Has anyone heard of gypsum? Is this a good idea? Is there any other recommendations I should do for these trees? I planted 15 GG last spring they all seem to be doing well, but I was told they are more tolerant to different soil types. Any help is appreciated.