Phyl,
I just looked up cityline and they say they are good in zone 5.

Stephanie Kay

Here is a link that might be useful: cityline

Well, I'm in 6b and what I said is based on my 4 years experience with all four of the Cityline.
First obtained them in 2006 as a rooted cuttings in 4" pots. Replanted in 2G and overwintered all 4 in a coldframe.
Spring 2007. Planted Berlin+Venice in ground and replanted Paris+Vienna in 3G. Took cuttings from Paris.
Spring 2008 (after warm winter). Venice didn't make it at all (roots were alive, but all 5 canes died). Berlin's canes survived, but all buds were dead. Replanted Paris in 5G and planted last year's propagated plant in ground. Vienna still is in 3G.
Spring 2009 (after long and cold winter). Berlin died almost to the ground. Paris (in ground) died to the ground, though plant was young to begin with and winter was too harsh. Both potted plants (Paris+Vienna) overwintered perfectly and blooming right now.

IMO, of all four, only Paris and Vienna worth the trouble with overwintering. Neither Berlin nor Venice show anything distinct, just a regular pink mopheads.
Paris is a compact 2-2.5' shrub with very bright raspberry red flowers and Vienna is a true dwarf (1.5x1.5') with pinkish-red (though not as bright as Paris) proportionaly smaller flowers.
FWIW.
Paris
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Feel free to mail them my way if you don't want them. : )
I saw Cityline Paris at a nursery in bloom and LOVED the color. Did you leave yours in the ground or in pots over the winter Phyl? If they were in the ground and made it through their first winter, that's encouraging. With hydrangeas though, it seems there are some that are "hardy" in your zone but they just don't bloom. I've seen a couple other comments besides Ego's that say the Cityline series is not reliably hardy in zone 5.

In general, hydrangeas get hardier with age and if you're willing to cover your Citylines with burlap or leaves (or maybe both) in the winter and give them a few years to get established, you might be the envy of your neighborhood when (if) they start blooming. They're supposed to be low-growing so that should make them easier to cover in the winter than a large one would be. You have to be sure to protect them from late freezes in the spring.

Gardenweb has a Hydrangea forum. You may want to search that forum for comments on Paris. Best of luck.

stephanie, dontcha hate it when they advertise something as z.5 hardy; but leave out the part that it's only root hardy!

ego, thanks for your detailed experience with cityline ~~ i am not feeling hopeful; especially since the nursery only had venice left ~ they were small plants last fall, so i had no trouble completely covering them with a thick blanket of mulched leaves ~ but i can't remember now if they were dead to the ground in the spring when i uncovered them or not (???) ~~ anyway, they had now 12 to 18 inches tall, with no sign of buds ~~ btw your pictures of paris are gorgeous ~ that is the one i wanted!

christie, i guess i have answered your questions above ~ yes, i do peruse the hydrangea forum; but i guess i wasn't paying attention when zone hardiness for cityline was discussed! (grin) hey, don't forget to ask me next yr. if i've given up on cityline ~ (but they are venice, unfortunately: not that beautiful paris that ego has) & i will ship them along to you ~~~~

thanks again for answering, phyl