My better local garden stores have their best selection of potted-up roses
in late March/Early April (zone 6a). But our last frost date is not until
May 15. So every year I play this game where I dig the holes, put new roses
in, pot and all, and watch the weather like a hawk, ready to move all the
new ones into the garage attached to our house (unheated) at night, then
being made somewhat late for work by waiting until the temps are above 30 or
so to put them back out again, sometimes having to leave them in the garage,
just for one day (seems not to have any negative effect).

Questions:

(1) I've read that anything below 28 degrees F will do damage. So I bring
the plants into the garage whenever the forecast is for 34 or lower,
figuring that will cover any local microclimate issues. Am I being too
conservative?

(2) Is there some better solution I'm missing? It's tiring to move a dozen
pots back and forth on a daily basis.