A few years ago when we moved in we had a large and happy raspberry patch. After a few years it got overgrown and weedy so I thinned, weeded and spread hemlock bark to help keep the bark down. It has been two years and the bushes have either died or our barely holding on. I have even bought new plants, but they don't grow either. What can i do to revive my raspberry patch. I am attaching pictures of the sad plants. You may see in the background, along the fence my neighbor's very happy plants only a couple feet away.