My son and I were going through the yard at the new place we moved into this past fall. This spring is when we started going through and clearing out brush and such. He asked how I knew a shrub was dead by looking at it with no leaves on it. I told him this "If I can bend the branch and it is flexible and bends/bounces back to where it was, it is still alive. If I bend it and it breaks, then it is dead." I showed him on several shrubs we had that had been choked by vines. On those that broke I showed him that the inside of the branch lacked any green coloring. He enjoyed bending the branches of many shrubs and removing anything that broke. He was also happy a few weeks later to see leafing on the branches that were "flexible". LOL Others may do it differently, but that is how I have always done it.