These aren’t your grandma’s hydrangeas.
In a wide range of forms and color combinations, this old-time shrub is enjoying a resurgence, thanks to new varieties that can take more heat (or cold) with less water. These recent introductions have made hydrangeas must-have additions to landscapes coast to coast – even in California.
“It’s a big year for hydrangeas,” said Kate Karam of Monrovia Nurseries, the wholesale nursery giant. “We’ve sold out of a lot of them. ... There are still a few holdouts such as San Diego that haven’t embraced them yet, but everywhere else, hydrangeas are really hot.”
Intriguing to gardeners for their color-changing flowerheads, hydrangeas have become among Monrovia’s most popular ornamental shrubs. The color and form of these new hydrangeas stretch way beyond basic pink, white or blue to multi-colored petals and flowerheads that change color with the season, not just soil conditions.
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Hydrangea mania already has deep roots elsewhere around the nation. Gardeners voted Tuff Stuff, a new lace cap variety that can thrive in weather extremes, the 2017 national champion of “Shrub Madness” as America’s favorite shrub. Conducted by plant company Proven Winners, the online bracket-style competition pitted all kinds of shrubs – from arborvitae to weigela – against each other in a leafy version of basketball’s March Madness. Let’s Dance Diva, another lace-cap hydrangea, won the 2014 title.
What makes these hydrangeas garden champions? They offer a lot of color with little work. They’re workhorse shrubs, framing gardens with vibrant hues. They also can take star turns with dramatic displays of eye-popping flowers in shady spots where other plants refuse to bloom.
“Obviously, people love their big, beautiful blooms and fast growth,” Karam said. “They’re long-lived plants, too, which means they’ll look good for several years. And one of the really lovely things about hydrangeas: They’re just so tough.”
Among Karam’s favorites: Blue Enchantress, a vibrant blue with blackberry-hued stems, and Monrovia’s Seaside Serenade series of compact varieties such as pink-picoteed Fire Island. Those bushes stay under 3 feet tall and fits better in today’s smaller yards.
Also popular is Incrediball, which produces fluffy white snowballs the size of dinner plates.
This new generation of hydrangeas really is different, she noted.
“The leaves are different,” she said. “They’re thicker, waxier. Some are fuzzy. That allows the plants to tolerate more wind and sun, and need less water.”
Hybridizers found certain hydrangea species could withstand a broader range of weather conditions than others and started breeding new varieties with those attributes. These hybrids also have stronger stems to support bigger flowerheads and not flop over. Those improvements helped spur the recent plethora of new introductions.
“Plant breeders unlocked the key,” Karam said, “but it was 100 percent driven by consumer demand.”
Hydrangeas, as their name implies, like water. These shrubs will wilt when soil moisture dries out too much. During California’s prolonged drought, gardeners pulled out a lot of hydrangeas in favor of more drought-tolerant landscaping.
“Once established, a lot of hydrangeas are drought-tolerant, especially these new varieties,” Karam said. “But they do need consistent water to get started.”
In Sacramento, our wet winter and spring revived local hydrangeas to past glory.
“The hydrangeas have never looked better,” said Carmichael’s Ellie Longanecker, a UC master gardener for Sacramento County. “They are so incredible this year – and big. My Limelight is two feet taller than my 6-foot fence.”
Longanecker grows 16 hydrangeas under a massive walnut tree and other shady spots in her garden.
“My neighbor’s redwoods shade part of our yard,” she said. “I tried growing roses in that spot, but gave it up; they struggled with that shade. I planted hydrangeas instead and they’re really happy. They love the redwoods. They get just enough morning sun and afternoon shade.”
During the recent heat wave, Longanecker set up umbrellas to shelter hydrangeas in the sunniest spots.
“I was surprised they survived the heat, but they look fine,” she said.
With old-fashioned mophead hydrangeas, pruning could be problematic, Karam said. Traditionally, they need to be pruned in summer after their flowers fade. If pruned at the wrong time, they could go a year with no blooms.
Most newer varieties are re-blooming, which means they’ll set more flowers after the first flush of spring. They also can be pruned in fall, winter or early spring and still bloom the following summer.
Although hydrangeas are considered a shade plant, they do need some sun (preferably morning) to bloom consistently, Karam noted. Feeding once a year in summer with a fertilizer high in phosphate is enough to keep the bushes thriving.
As for water, they need an inch of irrigation a week – the same as tomatoes.
“The only real trick with hydrangeas is getting the water right,” Karam said. “They don’t like it too dry or too wet. They want it just right. Grown in containers, they may need water every day. But in the ground, give them a deep, slow soaking once a week and that’s plenty.”
How to make hydrangeas change color
Hydrangeas have a unique trait: Their blossoms can change color. This is a reaction to soil acidity. Acidic soils such as near pine or redwood trees produce blue flowers; alkaline soils (such as heavy clay) prompt the flowers to be pink.
White hydrangeas stay white (or shades of green), but otherwise, most hydrangeas will react to soil acidity, explained Kate Karam of Monrovia Nurseries.
“I love messing with hydrangea colors,” she said. “You can get some really interesting results. But you need to be consistent and patient. It doesn’t happen overnight.”
Generally, aluminum sulfate is added to acidify soil, lowering its pH level to below 5.5 (6.5 is considered neutral).
“This can take years – years – of consistently applying it, a little at a time,” Karam said. “People see hydrangeas at the nursery in bright blues, but (the plants) have already been forced into doing that color. If you want a blue hydrangea to stay blue, plant it under a pine tree.”
Karam suggested experimenting to find the right soil acidity and perfect color. With applications of aluminum sulfate on only one side of the bush, pink and blue flowers can be grown on the same plant.
“It’s a little trial and error,” she said. “When you start, you tend to make them purple.”
– Debbie Arrington