This is Prunus mahaleb. It was a tree about 4 meters high. A friend collects these in Italy. He cuts the trunks back to stumps without a branch and without a bud. But they will bud back easily. I acquired this one four years ago as stump with a few slim branches. Today it certainly is not much of a bonsai yet, but it has gret potential. We'll see. At present it is 50 cm high.
1 and 2) Late winter 2006
3) Spring 2006
4) February 2007
5) March 2007