I give mine a small watering every month.I am in zone 6. I have had good luck for years doing this. lesley

Water them! Even though they're dormant and you have them protected in the garage they're still drying out and that can kill them as surely as winter freeze and thaws can. Roses outside in the snow and rain continue to get watered all winter but you need to see that the ones inside get water. As Lesley said, it does not have to be a lot but they will need moisture. I have one inside my shed and we regularly put a shovelful of snow on the pot. If there is no snow I haul out an old gallon milk jug of water and pour it on about once a month.

Stick your index finger in the soil as far as it will go. That should tell you whether it needs watering or not. Plants need to be moist in the Winter, not dry out but they also dare not be sopping wet.

Cath