Having no idea what your soil or drainage may be like I can only tell you what I do here in well drained clay loam soil. I start with an area 4 x 4 feet and mix finished compost to a depth of 2 feet, about 50% compost to soil. In your zone I think you would not want the eyes more than 1 to 2 inches deep. Here the eyes are at soil level. I do not add anything other than compost to my garden soil and will replenish it spring and fall AROUND the peony not on top of the buds. Al