70-75 species
Native: Asia, Portugal
Flowers grow in flowerheads (corymbs or panicles) at the ends of the stems.
In these species the exact colour often depends on the pH of the soil;
acidic soils produce blue flowers,
neutral soils produce very pale cream petals,
and alkaline soils results in pink or purple.
Hydrangeas are one of very few plants that accumulate aluminium.
Aluminium is released from acidic soils, and in some species, forms complexes in the hydrangea flower giving them their blue colour.
(Excerps From Wikipedia, the free encyclopedia)
Species...
Hydrangea arborescens (Smooth Hydrangea). Eastern North America.
Hydrangea aspera. China, Himalaya.
Hydrangea bretschneideri. China.
Hydrangea candida. China.
Hydrangea caudatifolia. China.
Hydrangea chinensis. China.
Hydrangea chungii. China.
Hydrangea cinerea (Ashy Hydrangea). Eastern United States.
Hydrangea coacta. China.
Hydrangea coenobialis. China.
Hydrangea davidii. China.
Hydrangea dumicola. China.
Hydrangea gracilis. China.
Hydrangea heteromalla. Himalaya, west and north China.
Hydrangea hirta. Japan.
Hydrangea hypoglauca. China.
Hydrangea integrifolia. China.
Hydrangea involucrata. Japan, Taiwan.
Hydrangea kawakamii. Taiwan.
Hydrangea kwangsiensis. China.
Hydrangea kwangtungensis. China.
Hydrangea lingii. China.
Hydrangea linkweiensis. China.
Hydrangea longifolia. China.
Hydrangea longipes. Western China.
Hydrangea macrocarpa. China.
Hydrangea macrophylla (Bigleaf Hydrangea). Korea, Southern Japan.
Hydrangea mangshanensis. China.
Hydrangea paniculata (Panicled Hydrangea). Eastern China, Korea, Japan, Sakhalin.
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 stenophylla. China.
Hydrangea strigosa. China.
Hydrangea stylosa. China.
Hydrangea sungpanensis. China.
Hydrangea xanthoneura. China.
Hydrangea zhewanensis. China.