This section is from the book "The Gardener's Monthly And Horticulturist V26", by Thomas Meehan. See also: Four-Season Harvest: Organic Vegetables from Your Home Garden All Year Long.
One might say that anything is as much alike as two snowballs, as to put it in the more common form, as "like two peas," but the Japan Snowball is very unlike the common one, and is withal very beautiful.
Apropos of your note, p. 197, I would say that the Japanese Snowball (V. plicatum) is very much finer than the American one (V. opalus), but if possible Viburnum rotundi-folium is finer than plicatum. At any rate it comes into bloom a few days earlier, and, judging by our plants, the snowballs are larger. When they first begin to leaf out the leaves of rotundi-folium and plicatum are very much alike, but as they advance in weeks they differ in form and the lower leaves of rotundifolium are almost perfectly round. Our plants of it are of the variegated variety.