While there are approximately 23 species of Hydrangea, only five are widely cultivated in the U.S.

The most popular species is Hydrangea macrophylla, which is commonly known as mophead hydrangeas. Mopheads produce large inflorescences of white, pink or blue flowers in early summer.  The inflorescence is composed of a combination of large, showy and small, inconspicuous flowers.

Lacecap cultivars (H. macrophylla var. normalis) have an inner ring of small, fertile flowers surrounded by an outer ring of large, showy flowers. Growing 4 to 6 feet in height and width, both mophead and lacecap hydrangeas can be used as specimen plants, in mixed borders or in mass plantings.

Panicle Hydrangea

Panicle hydrangea (H. paniculata) is the cold hardiest member of the genus, and can be reliably grown in Michigan. They grow 10 to 15 feet tall, and during mid-summer produce large creamy-white flowers on long panicles. 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 are great for a mixed border or as a deciduous hedge.

Smooth Hydrangea

Smooth hydrangea (H. arborescens) is the other U.S. native. Plants usually reach about 5 feet in height, with a similar or greater spread. Flowering occurs in early to mid-summer. The most common cultivar, ‘Annabelle’, produces rounded inflorescences that may reach up to a foot in diameter. At the peak of flowering, smooth hydrangea flowers are a pure white. As they age, they develop a pale green color. These plants are extremely striking in mass plantings.

Oakleaf Hydrangea

The oakleaf hydrangea (H. quercifolia) is one of two Hydrangea species native to the U.S. They’re found growing primarily in moist woodlands in the southeastern U.S. Plants generally grow 6 to 8 feet in height and produce large (4 to 12 inches in length) panicles of creamy white flowers in early summer.

As flowers age, they often turn a medium- to deep-rose color. Oakleaf hydrangea is the only member of the genus to develop significant fall foliage color. Leaves turn a deep mahogany-red and stay on the plant until late fall. Exfoliating bark adds to winter interest. Oakleaf hydrangea is best suited used in a mixed border or as a mass planting.

Climbing Hydrangea
Climbing hydrangea (H. anomala subsp. petiolaris) is becoming increasingly popular.  It’s a true clinging vine. While initially slow growing, the plant can eventually cover tall (up to 80 feet) structures. White, lacecap type inflorescences are produced in early- to mid-summer. Plants can be slow to flower, but patience is rewarded by a spectacular floral display on established plants. Climbing hydrangeas grow well in shade, but can also tolerate a sunny location.