I took a close look at my weigela, and saw this cane. At first I thought it was just the normally variegated leaves reverting to completely green, but then I noticed the leaf pattern is different, 3 leaves per node, instead of 2. The cane is about 6 ft tall. It's quite brittle -- I wiggled it, and it snapped (oops). This is the cane lying on the ground. (I don't think this bush has ever been pruned.) Going off on a tangent - I'm amazed that these snails climbed 6ft up. Thanks. - A newbie gardener, overwhelmed by her boyfriend's 'low-maintenance' garden. Read lots of books, but sometimes you just have to ask.
Maybe a rootstock shoot growing out from under the grafting point? If you want the bush to stay variegated, then you did the right thing in removing it.