Somebody’s stairs to the gate were covered in flowering sedum today, wow. I think these are Kamtschat sedum or Sedum kamtschaticum (from northern parts of East Asia)
There are 400 species of sedum found throughout the northern hemisphere. European sedums such as Stonecrop are particularly known in gardens.
See Wikipedia for more info.
This link will show you the kinds of sedum available in Japan.
NATURE IN JAPAN 