I have Blessed Thistle, Borage and Gopher Purge volunteering this fall in my greenhouse cold frames. I live in Sandpoint, Idaho, Zone 6. These plants have germinated as volunteers this fall that I want to dig up and pot for either inside the house or into a cold attached greenhouse that irregularly gets heated by a woodstove when it gets real cold outside. The plants are Blessed Thistle, Borage and Gopher Purge. My question is "Are these plants too tender to dig up at all?" "Could they possibly die back and grow again in the spring even if they are annuals?" "Can I successfully grow them in a 60º or lower house in a window? Or in a cold attached greenhouse where I put all the potted herbs I haven't sold. Some die. Some live barely. Some die back and regrow well in the spring.