The new growth from the roots of the broken tree peony is definitely still from the tree peony not the rootstock. I know they are grafted but they do have their own roots when first grown from seed so I was curious about the broken branches rooting as they are flat on the ground and barely attached to the root understock. Last fall the broken stems still looked healthy and strong with large buds for this coming years growth so I covered the branches with some mulch. I also covered the tips with a large pot to protect them from heavy snow ( who knew we wouldn't have any this year) and they still look strong and healthy. I guess time will tell.
