Last year I had trees come early, and planted them. They were coming out of dormancy, had flower buds even. They went back into dormancy. Came out on time and grew well last summer. I wasn't sure what to do either, so I emailed Michigan State University home garden services. They told me to plant them. It was about March 7th in zone 6a. Last frost was April 29th last year, so temps dipped down to 28 degrees a couple times. Tree seem to have no problems at all. So I guess I would plant them if you can work the ground.