Information from both "Hydrangeas for American Gardens," by Michael A. Dirr (2004) and "Encyclopedia of Hydrangeas" C.J. and D.M. Van Gel...Read Morederen (2004 - Timber Press).
'Unique' was grown and introduced in 1968 by the de Belders for its large, pure white sterile florets (about 2" across) and rounded sepals. The showy sepals almost completely conceal the fertile flowers. The inflorenscences may reach 16 inches long by 10 inches wide. A fairly large shrub which should grow 10 - 14 feet high. Later flowering, approximately mid-July in zone 7b.
This cultivar is horribly confused in nursery commerce, and seldom is the true form. Prof. Dirr comments in the above publication that he has grown 3 so-called 'Unique' shrubs, none were true to description above. He states that Ted Stephens, Nurseries Caroliniana, North Augusta, SC was able to secure the true 'Unique' from the curator of Hillier Arboretum, and now offers these as true Unique (see 'True Unique').
Van Gelderen, in the above text states that the cultivar is a medium-sized shrub up to 8' and at least as wide, with weak branches (which is why the plants are often very wide). Flowers are creamy white, in large panicles. As these two descriptions are at odds with the plant size and color of the panicles, it should be up to the individual gardener to decide whether s/he has the true cultivar or not.
Information from both "Hydrangeas for American Gardens," by Michael A. Dirr (2004) and "Encyclopedia of Hydrangeas" C.J. and D.M. Van Gel...Read More