I have a very large vigorous female Arctic Kiwi which is at least 8 years old. I have planted a male Kiwi next to her in a bed beside the house . I have been unsuccessful in keeping a male alive. I have replaced 4 males to date. They are always spindly and weak. I have babied them but they all winter kill, some don't even make the summer! I live in northern B.C. Any suggestions?