I bought quite a number of tubers from a local dahlia organization's plant sale. When I planted them,two looked questionable. Both were sprouted. One has a healthy looking green spout, but the mid section of the tuber was soft. The other spout was strangely black, and the tuber was on the soft side. Is there a chance for the one with a black sprout? The variety is Tarahiti Ruby. That woulsn't be a variety with really dark foliage? I planted them both, and perhaps that wasn't the best choice.