A few years ago I dug up some raspberry shoots from a friends house and planted them in my garden. Every year they grow to about a foot and get 5 or 6 leaves then wilt and die. I got tired of waiting for them, so I bought 2 heritage red raspberry plants and planted them about 6 weeks ago. They have brown, dead looking canes and are about 8 inches tall with just a few leaves on each, but they don't seem to be getting any bigger. They don't seem to be dying either, just not growing. Am I doing something wrong? I've never grown raspberry plants before and I can't find anything online about why they're just sitting there. I am in zone 6.