longipes – western China Hydrangea macrocarpa – China Hydrangea macrophylla – (bigleaf hydrangea) southeast Japan, southern China Hydrangea mangshanensis – China Hydrangea paniculata – (panicled hydrangea) eastern China, Japan, Korea, Sakhalin Hydrangea peruviana – Costa Rica and Panama, Andes Hydrangea petiolaris – (climbing hydrangea) Japan, Korea, Sakhalin Hydrangea quercifolia – (oakleaf hydrangea) southeast United States Hydrangea radiata – (silverleaf hydrangea) southeast United States Hydrangea robusta – China, Himalaya Hydrangea sargentiana – western China Hydrangea scandens – southern Japan south to the Philippines Hydrangea serrata – Japan, Korea Hydrangea serratifolia – Chile, western Argentina Hydrangea strigosa – China Hydrangea stylosa – China Hydrangea tarapotensis – Andes Hydrangea xanthoneura – China Hydrangea zhewanensis – China Fossil record Hydrangea alaskana is a fossil species recovered from paleogene strata in Jaw Mountain Alaska. Four fossil seeds of Hydrangea polonica have been extracted from borehole samples of the Middle Miocene fresh water deposits in Nowy Sacz Basin, West Carpathians, Poland. Cultivation and uses Hydrangeas are popular ornamental plants, grown for their large flowerheads, with Hydrangea macrophylla being by far the most widely grown. It has over 600 named cultivars, many selected to have only large sterile flowers in the flowerheads. Hydrangea macrophylla, also known as bigleaf hydrangea, can be broken up into two main categories; mophead hydrangea and lacecap hydrangea. Some are best pruned on an annual basis when the new leaf buds begin to appear. If not pruned regularly, the bush will become very 'leggy', growing upwards until the weight of the stems is greater than their strength, at which point the stems will sag down to the ground and possibly break. Other species only flower on 'old wood'. Thus new wood resulting from pruning will not produce flowers until the following season. The following cultivars and species have gained the Royal Horticultural Society's Award of Garden Merit under the synonym Schizophragma: S. hydrangeoides var. concolor 'Moonlight' S. hydrangeoides var. hydrangeoides 'Roseum' S. integrifolium Hydrangea root and rhizome are indicated for treatment of conditions of the urinary tract in the Physicians' Desk Reference for Herbal Medicine and may have diuretic properties. Hydrangeas are moderately toxic if eaten, with all parts of the plant containing cyanogenic glycosides. Hydrangea paniculata is reportedly sometimes smoked as an intoxicant, despite the danger of illness and/or death due to the cyanide. The flowers on a hydrangea shrub can change from blue to pink or from pink to blue from