Common Name: 

About 100 species of evergreen or deciduous shrubs, also small trees or climbers, often with exfoliating bark when mature.  Leaves simple, opposite or in whorls of 3, usually rounded-ovate, entire or toothed.  Fertile flowers are rather inconspicuous, in contrast to showy infertile flowers which are usually arranged on the outer ring of the cluster (corymb or panicle).  Fertile flowers are bisexual with 4-5 sepals, 4-5 petals, small, white, blue, or pink.  The conspicuous part of infertile flowers is often enlarged, colored, with petal-like sepals, true petals may be much reduced or absent.  Fruit is a many seeded capsule.  Native to China, Japan, and Himalaya, Philippines, Indonesia, and North and South America.
Hydrangea: from Greek hydor, water and aggeion, vessel; a reference to the cup-shaped fruit.