If you can't wait to let it grow a bit longer because of weather go ahead and bury it. You want the crown to be under the soil by two or three inches.

I'm not in Montreal, but would probably baby it like this: plant it deeply so that the green parts are about 2" below ground level, but I'd leave them uncovered to photosynthesize until they've succumbed to frost or grown above ground level. Then I'd mulch/cover them up. The more sun it can photosynthesize the more energy it has to grow. Good luck! HFY is a nice bluish flower.

Thank you both for your advice! I went ahead and planted it just as you said, and will keep my fingers crossed. If this winter is anything like the last one, everything should also be well-buried and protected under lots of snow.

Judith