Do you have the ability to plant them in the ground on your south facing side of your house, close to the foundation??
Despite our wacky warm/cold/really cold cycles last year, I had great growth on most stuff by mid March in my zone 5A/5B garden.
I also one year got a plant that I was told could be temperamental..... and it was coming from further north than me. So for the first 3 winters, I would literally make a greenhouse for it, using a large clear plastic container with a few slits to allow for air circulation and no build up of condensation. I added lots of mulch and leaves around it and it appeared to do well. Last winter I didn't give it this special treatment and this year, it didn't bloom for me!!
