Winter protection is a must in Zone 5 because all the stems will otherwise originate from the crown or base. Apparently the amount of protection was insufficient so all the stems died to the ground. You did not say how you winter protected them. If you build a cage around the shrub, piled on leaves/mulch/etc and top it off with cardboard, it sounds like you need more separation between the cage and the stems plus more leaves/mulch/etc.. Extra material should be kept in a plastic bag so you can add more leaves/etc in the middle of winter as the material settles in time. Do a search in the forum for words like winter protect to see what others in cold areas have done.

This post was edited by luis_pr on Sun, May 26, 13 at 12:30

Could be not enough water or fertilizer? Good soil as in looks good or has it been chemically tested?

What are some neighboring plants and how are they doing?

Thanks for the followups. In response to Springwood, I have shrub roses in the west facing border and they are thriving; the east facing border has problems keeping anything alive so that is likely the trouble there (the neighbor throws their snow off the driveway on that border and the salt kills everything). The ones in part shade are in a shrub border under the shade of dappled willow standards. Everything in that border is thriving and the soil is really good.
I think Luis may have a point. Winter protection is likely the key. My sister has all of hers planted as foundation plants and she lives only 1 hour south of me. Hers thrive!

You are right about the need to protect. You sister 's foundation plants also get some help there.