Viburnum plicatum plicatum is the sterile form with creamy white flowers in balls; in V. plicatum tomentosum the flowers are fertile in flat heads with sterile florets forming a ruff, like a lace-cap hydrangea. I grew V. plicatum 'Lanarth' (a form of tomentosum) for its fabulous tabulated form, branches making many flat tiers of growth - very striking. It never set any berries (but neither does V. plicatum plicatum). Graham Stuart Thomas (in his 'Ornamental Shrubs, Climbers and Bamboos') says that you need two or more clones of V. plicatum tomentosum to get berries, so that explains the lack of berries for me.
I sense that the plicatum tomentosum forms, especially the selected forms, may be more strikingly tabulated than the plicatum plicatum forms - more architectural if you like, accentuated by the flat flower heads. My shrub wilted alarmingly in any dry period!
