I have two Annabelle hydrangeas that have been growing for a long time and do quite well on the west side of the house with a layer of gravel on top of black plastic. I'm wondering if this allows them to get through the winter and both are sending out leaves on last year's growth. I was thinking of removing the plastic and putting the gravel in the driveway to fill in the ruts as the gravel matches the driveway gravel and also, I wouldn't have to buy and haul more gravel for the driveway. Would replacing the plastic and gravel with wood mulch give the same insulating qualities of getting the plants through our unpredictable winters? Or should I just leave them alone? I wouldn't have to haul woods chips as I have plenty of trees that need chipping up rather than simply burning them. What are your thoughts and both of these hydrangeas send out suckers and I was considering digging them up and planting in the same bed .