It could be any number of hardy stonecrop variety, the 2 listed above are quite common, so there's a good chance it could be one of those, I'm not so sure a bloom will help much, they almost all look the same to me...
I doubt you'll rot it off, if you do just cut it back and reroot it... These are fairly indestructible, even a lawnmower is no match for em! They just spread more!
I just had to cut all mine down as they are choking out their neighbors...
I planted as many as I could be tossed a bunch... All you gotta do is stick a cutting in the ground and it's as good as established!
