goldenrod gall fly larvae are freeze tolerant. In this bitter cold weather they are frozen solid. If you drop a pea-sized larva on a hard surface, it "plinks". But, warm one up, and soon it is moving around. That is a very different winter survival strategy than the willow pine cone gall larvae. Notice the larva's escape tunnel that it excavated in preparation for spring, when it will be a fly without a means of chewing out of its home.
Chickadees and woodpeckers peck holes in the galls to feed on the larvae.
Fence rows are fascinating.
John Eastman gives more details about the goldenrod in the Book of Field and Roadside