As I travel around this summer, I can’t help but notice what a spectacular showing the many varieties of hydrangea are putting on. This family of plants has come far in the last decade with many new varieties and sizes available now.
Hydrangea macrophylla, commonly known as bigleaf, French, garden or florist’s hydrangea, is a Japanese native is rated as hardy to USDA cold-hardiness zone 6. It produces large inflorescences of white, pink or blue flowers in early summer composed of a combination of large, showy and small, inconspicuous flowers. In mophead, or Hortensia, (H. macrophylla var. macrophylla) cultivars, many showy flowers are arranged on the outside of the rounded inflorescence. On the interior of the inflorescence, a few small flowers are present; these are the flowers that produce seed.
Hydrangea paniculata is the most cold hardy member of the genus. It can be reliably grown in USDA cold-hardiness zones 4 to 7. Native to Asia, it grows 10 to 15 feet tall. Large creamy-white flowers, which are borne in 6- to 18-inch long panicles, are produced in mid-summer. As flowers mature, they may turn pink. Plants, particularly those of the cultivar 'Grandiflora' ('Pee Gee'), are sometime pruned into a tree form and grown as a specimen plant. Panicle hydrangea is also suitable for use in a mixed border or as a deciduous hedge.
Hydrangea quercifolia is one of two Hydrangea species that is native to the U.S. It is found growing primarily in moist woodlands in the southeastern U.S. Plants generally grow 6 to 8 feet in height, although a few cultivars with smaller and larger plant habit are available. Large (4 to 12 inches in length) panicles of creamy white flowers are produced in early summer. As flowers age, they often turn a medium- to deep-rose color.
Hydrangea arborescens or smooth hydrangea is the other U.S. native. It is found in the eastern U.S. from New York to Florida and west to Iowa and Louisiana. In cultivation, plants usually reach about 5 feet in height, with a similar or greater spread. The species is rated as hardy from USDA Cold Hardiness Zones 4 to 9. Flowering occurs in early to mid-summer. The most common cultivar, 'Annabelle', produces rounded inflorescences that may reach up to a foot in diameter. Plants found in the wild typically have a lacecap type inflorescence consisting of a combination of a few large and many small flowers. At the peak of flowering, smooth hydrangea flowers are a pure white. As they age, they develop a pale green color. Smooth hydrangea is extremely striking in mass plantings.