It's latin name is V. plicatum var. tomentosum, or "double-file viburnum" so named because it's flowers, blooming in May here, line the tops of the branches in a double row. The flowers are the most distinctive characteristic of viburnum -- always white or pink, arranged in clusters of both sterile and fertile flowes. In the double-file viburnum, the clusters are flat and white with the larger sterile flowers forming a ring around the inner fertile ones.
Many viburnums also produce berries and in the fall this tree
will be decorated with clusters of red fruits that will turn black
as they mature.