, 1868 The term
macrophylla means 'large- or long-leaved'. The opposite leaves can grow to in length. They are simple, membranous, orbicular to elliptic and acuminate. They are generally serrated. The natural
inflorescence of wild
Hydrangea macrophylla is a
corymb, with all flowers placed in a plane. Two distinct types of flowers are found; numerous central, small, fertile
pentamerous ones, and a few peripheral, large,
tetramerous ones; the latter are usually sterile, and whitish to pale blue or pinkish. The small flowers have five small greenish sepals and five small petals. Flowering begins in early summer and lasts until early winter. The fruit is a subglobose capsule. In cultivation as an
ornamental plant, numerous variants have been developed as
cultivars; in most of these (over 500 cultivars), the small central flowers replaced by large, sterile or mostly sterile tetramerous flowers, the inflorescence forming a hemisphere or a whole sphere rather than in a flat plane. These cultivar groups are known as "mophead" or "hortensia" hydrangeas. These large flowers have colours ranging from pale pink to red, fuchsia, purple, to blue. A much smaller cultivar group (over 20 cultivars), known as "lacecap" hydrangeas, retain the natural form of flat flowerheads with small flowers surrounded by a halo of large sterile flowers, but varying from the wild plants in more intense colours. Some cultivars (possibly many, and particularly those selected for greater cold tolerance) derive from
hybrids between
Hydrangea macrophylla and
Hydrangea serrata, the hill hydrangea of the mountains of Japan. == Colour and soil acidity ==