This year I have manually started to start spreading my sedums out, and actually cutting back on the original one since it keeps expanding. They are very hardy so zone 6a winters are usually never a problem especially since they grow so low to the ground and get covered by the snow. All of them made it through the winter except the Angelina, but I have re-acquired that species so it's OK.
Here's the original sedum that I started out with.
Sedum Sarmentosum
