When we think of hydrangeas, most of us think of the old-fashioned "mophead" type, blowsy with oversized puffball flower heads -- a shrub in a clown suit. But the hydrangea family is huge and offers an array of options, both shrub and vine, that can enhance a corner, cover a wall, or offer three-season beauty in a border.
Flower heads vary from soccer-ball clumps, to panicles (drapey conical clusters of blossoms) to delicate lacecaps whose flat-faced blooms look like the frilly doily on a French maid. There is even an evergreen hydrangea, a climbing species with a deep purple undersurface to its foliage, that plant hunter Dan Hinckley discovered in Vietnam.
"We're still deciphering this remarkable group of shrubs and vines that shout for a greater audience," Hinckley says.
A broad-based family
While many hydrangeas originate in Japan, China, Vietnam, the Himalayas, and Korea, two types -- Quercifolia and Arborescens, the 'snowball' hydrangea -- are native to the U.S. But native or import, most hydrangeas thrive here.
"Petiolaris types, especially 'Anomala' grow well almost everywhere," says Kristin Van Hoose, owner of Hydrangeas Plus in Aurora, Ore., which sells 80 varieties. "They are climbers with beautiful white lacecaps. But they are not invasive and won't take the siding off the house like wisteria."
"Petiolaris bark is beautiful too," adds Alan Summers, owner of Carroll Gardens in Westminster. "They need some shade and take several years to get going, but once they get going, they really go. I've seen them at the top of a 3-story stucco house."
Despite their summertime beauty, (hydrangeas start blooming about mid-June) Summers suggests grouping them with evergreens and grasses to keep them hidden in winter.
"They don't look like anything when they lose all their leaves, so don't use them across the front of the house," he advises, though some, like Oak leaf (Quercifolia) varieties have nearly year-round interest -- peeling cinnamon bark in winter, green leaves in spring, and creamy panicles in summer that dry to burnished pink in fall when the leaves turn a glorious crimson and russet -- and can be used in a front border buttressed with evergreens.
Cultivation and care
"In the wild, hydrangeas are generally found in woodlands," observes Hinckley, who has cultivated hydrangea strains from around the world in his garden in Washington state. Heronswood Nursery in Kingston, Wash., which Hinckley started, sells about 60 hydrangea varieties.
Woodland habit means most hydrangeas prefer dappled shade, though total shade can curtail bloom. They also do well here on the north side of buildings where they get early morning and late afternoon light.
"For the flowers to last, they need a little protection from mid-afternoon sun," says Summers. "Otherwise they wilt and that shortens bloom time and reduces the number of flowers."
Moist, well-drained soil is another key to keeping hydrangeas happy.
They want about an inch of water a week, (which is the ideal for almost everything but desert stuff). But once they are established (after 2 or 3 years) some, like the smaller Serrata types, are fairly drought resistant.
One of the fun things about hydrangeas is that most change bloom color in response to pH changes in the soil, so you can tinker.
"If you add aluminum nitrate to the soil," says Don Howe, co-owner of Country Gardens in Fall City, Ore., "it increases acidity and increases the intensity of the blues."
"For lighter colors of pink," Hinckley says, "add about 2 cups of lime per planting hole to make the soil more alkaline."
Few hydrangeas need pruning, but if you must prune, Howe recommends cutting out only very old woody canes. To gauge timing to keep from shearing off the next cycle's buds, you need to know whether your particular plant blooms on old or new wood. Some varieties bloom on old wood and set buds in fall, (which can make them vulnerable during winters with wild swings of freeze / thaw). Others bud on new wood in February or March.
"Generally, the 'mophead' varieties form buds on old wood, which means they set buds the autumn before they bloom," says Van Hoose. Many lacecaps bud on new wood, and some bud on both.
"Paniculata and Arborescens bloom on both old and new wood. So they can be cut back to the ground if you want," says Howe. "And many gardeners like to deadhead [cut off spent flower heads], but letting hydrangea blooms dry on the stem can offer wonderful blooms for long-lasting dried arrangements."
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