I assume you mean roots and of course you can plant them in the spring. Often this is a more economical way of getting your plants.

Be forewarned however: the quality of some of these "bagged bareroots" can be a little suspect sometimes.

I just got mine from Brecks, They are awesome. All are growing great and it is cold out. I got the following plants.
Album~~2 plants
Patricia~2 plants
Splish Splash~2plants
Balleruna~2 plants
Johnson Blue~2 plants
The total cost with shipping was $38. Big healthy roots, all are doing great.

Freshy-dug and shipped from some professional nursery should be fine.

I cringe however, when I see bareroot perennials on those large racks of bulbs in the box stores! ;)

I agree with cpg. Many "bagged" perennials have very small, dried out roots that would be lucky to survive. Buying perennials potted in soil/soilless mix is much better. Some mail-order nurseries ship them this way now.