 Hydrangea flowers, when cut, dehydrate easily and wilt very fast due to the large surface area of the petals.A wilted hydrangea may have its hydration restored by first having its stem immersed in boiling water; as the petals of the hydrangea can also absorb water, the petals may then be immersed, in room-temperature water, to restore the flower's hydration.In most species the flowers are white, but in some species (notably "H. macrophylla"), can be blue, red, pink, light purple, or dark purple.