Prunus serrulata kanzan, Family – Rosaceae
A deciduous tree – and since it is sterile, it will not bear fruit. Native to Japan, Korea and China. It has pink double flowers in clusters of 2-5. Pretty avenue trees, but have shallow roots and not suitable for home gardens.
All information here is from Landscape Architecture Blog. Pictures were sent to me by S – and were taken a month ago in London in April.