I was just looking around this site and found this:
http://forums.gardenweb.com/forums/load/winter/msg1114575816797.html?7

Several replies about H&C's there,
I recently got some from Menards at a good price and planted them in the ground a little over a week ago. They should do ok here in St Paul. I will move them in the spring. One container I am keeping in the Kitchen south window and split a couple of chicks and they are in separate small pots. I will see how they doing over the winter there.
GL

wiley that is a nice link.

I have several different sempervivum plants and they do very well in the ground all winter. I did find that my first two years of trying them did not make it over the winter. Then I made a cactus and sempervivum garden by adding, gravel and sand to my garden soil and built it up enough that is drains very well.

I guess I would be cautious about leaving them in the sphere. It "feels" as if the roots wouldn't be protected enough in our cold winters.

My hens & chicks were in small pots which I popped into the ground in my holding bed before going on a vacation for a week. They had grown well in the pots all summer but now they look horrible. Either they have rotted or something has eaten them to the soil (I do have a deer & rabbits eating lots of things in that bed). Hens & chicks do not do well for me. These looked so nice that I thought, "maybe this year...".