It has to be Sempervivum - that is the only 'Hen & Chick' type succulents that would be cold hardy enough to live in your area. There are a ton of different ones. I found this website with photos - I have never purchased from this company so can't recommend or not recommend but the photos are worth a look.
http://mountaincrestgardens.co...
All the Sempervivums mound like that with time.
