We were puzzled for a while about the identity of this sedum, which appears to be a relatively new introduction that we never saw sold as a labeled plant, only in mixed trays at Lowes (and quite abundantly). We were going to wait until it flowers - a good practice for any identification work - to submit a request to the Name That Plant! forum, but since this question came up right now at the Raleigh Swap we are going to share some preliminary ideas. Maybe someone can help here.

As shown in the above picture, this sedum has a very unique leaf serration pattern that closely resembles the teeth of a saw. It is either deeper or more regular or both than a number of popular serrated sedums, such as S. middendorffianum, floriferum, and several others. There are a number of Google images labeled S. kamtchaticum that have this pattern (in particular ssp. ellacombianum), but not always and on our own S. kamtchaticum (from J L Hudson seeds), the teeth are shallower and more rounded, and the leaves are darker green. On the other hand, S. populifolium has wider and deeper gaps between the teeth. The closest candidate that shows consistently the saw-tooth pattern and lighter green leaf color in Google images is S. takesimense, but its picture from JCRA has much more elongated leaves. In addition, the book "Hardy Succulents" has on page 86 a similar looking picture labeled S. tatarinowii, but there are fewer Google images that support it.