Since you are talking about plants that would normally have spent the entire winter outside, so long as they are reasonably dormant, getting them outside too early isn't an issue.

Even if they have started to sprout, getting them out into the ground isn't a bad idea. The cold will slow them down and get them back on a more normal schedule.

Depending on your watering abilities, you might want to plant them first in one gallon containers to ensure good root growth then transplant to the garden in the fall that way you'll be sure to water faithfully.

Here is a link that might be useful: Propagating Perennials