Sucess in pots and a question.
Last fall I planted 2 peonies in 2 20" pots with my own potting mix: 20% of my native New England sandy and rocky soil, 25% of potting mix and the rest was the cheapest topsoil I could found, and couple cups of bulb booster. I covered with 2" of mulch and put they under the deck close to the foundation. These peonies were planted in my garden about 1 and half year,(I planted in spring, I didn't know better) and didn't have enough space to thrill. I dug up much of their roots. I was a little disappointed they only had 3 eyes or so, and roots were not really big. I had moved 3 other, but planted in ground.
I moved they out to a sunny spot in late March. I checked they were alive. Now they are shooting up more than 6 stems each, double the among the stems than those in the garden (I got them all in the same time).
Question: Why they are doing better than those in the ground?