This jbp was growing in a one-gallon nursery container for several years. The mix, which had broken down considerably, was composed of pine bark and perlite. I decided to put it in a bonsai container on March 15th. The new mix is the standard a/p/l. As I was getting into the root ball, I noticed that much of it was black and dead. I didn't go with the Boon method of half bare rooting. Instead, I tried Ryan Neal's method of leaving the root ball and soil under the trunk untouched. I teased out roots as best I could and surrounded the root ball with the new mix. Although it probably isn't advised, I've always left my jbps out on the ground covere with leaves during the winter. This year we had searing cold temps and one night saw -7 F. Is there anything I can do that might help improve survival chances? I considered taking it back out of the pot and planting in pure pumice. The needles have started drooping a bit and the shiny look that most jbp needles have is dulling. I fear the worst.