Hydrangea is a genus of about 70 species of shrubs, trees and climbers The flowers come in shades of blue, purple, white, pink and red. Their big, bushy head and charismatic flowering blooms in intense colors are magnificent for bouquets and arrangements. The species range in size from 60 cm to 12 metres (2 ft to 40 ft) in height, depending on species. Hydrangea grows best in moist, but well- drained soil.