This year I planted sweet potatoes for the first time. The vines are going crazy. In an attempt to keep them from taking over my garden I've been trying to keep them circled around "mounds". When i have been re-gathering them I noticed that the vines where they have been spreading are rooting. Are these small roots where potatoes will be forming or are they forming under original "mounds". Is it OK to keep redirecting vines so they don't take over garden?