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"I'm a Hottie" dahlias have 8-inch blooms of hot pink. (Photo by Don Cowles)
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Dahlias in an arrangement by Jane Cowles (Photo by Jane Cowles)
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Dahlia tubers (Photo via Getty Images)
Jane and Don Cowles are a couple of dahlia lovers. She — a longtime member of the Boxwood Garden Club in Richmond — creates arrangements with the flowers that he raises in the garden of their West End home. Married for 50 years, theirs is a symbiosis rooted in a shared love of nature. Dahlias have grown to be their favorite flower.
There is a lot to love about dahlias. In Central Virginia, they flower from June until first frost, producing an endless supply of blossoms to delight gardeners and floral designers alike. Their sumptuous blossoms are unscented, attracting pollinators and enchanting growers with their outrageous array of shapes, colors and textures.
The American Dahlia Society recognizes 19 different forms and 42 different species of dahlia. From diminutive 2-inch pompons to 10-inch “dinner plate” dahlias, there are varieties that are decorated with stripes and spatters and dahlias whose petals are dipped in contrasting color. Some dahlia blossoms are packed with geometric precision into vibrant pinwheels, while others have petals so spidery and sparse you can count them. There are fringed dahlias, mophead dahlias, prim pincushion dahlias and dahlias with centers that mimic their sunflower and aster cousins. They bloom in an explosion of color: red and pink, orange, yellow, white, purple, and even a “black” dahlia with dark red petals as lush as a vintage malbec.
Dahlias are native to Mexico and South America, where their tubers were once grown as a food crop by the Aztecs. The plant itself is bushy, producing as many as 10 to 12 blossoms. Dahlia blossoms are some of the longest-lasting cut flowers. “They are a splashy statement flower,” says Jane, noting her preference for designing with them. “A single bloom in a single bowl is spectacular.” She floats 10-inch dinner plate dahlias in shallow bowls or combines smaller forms with zinnias, hydrangea, mint, fern fronds, poet's laurel, bittersweet, angel wing begonia and eucalyptus.
“Dahlia tubers look like 2-inch-long sweet potatoes with eyes on one end,” Don says. He plants them in mid-April, lying 6 inches deep on their long side, eyes up. A stem emerges from the eye, producing blooms in 90 to 120 days, depending on the variety. “Stake them as they grow,” he recommends, “or the stems will snap from the weight of the heavy flowerhead.” Otherwise, dahlias require very little tending. Plant them in well-drained soil where they will get eight hours of direct sunlight. Water them after they break ground in the spring, and then only when they are dry. They are immune to most garden pests; deer eat them only out of desperation.
After the first frost, Don cuts his dahlias off at ground level, leaving the stakes in place to mark the location of each tuber. He covers the tubers with plastic sheeting topped with a layer of mulch to prevent moisture rot.
“And then comes the curious part,” he says. Below ground, all season long, the tuber has been quietly reproducing, expending so much energy that its shoots come up spindly and sparse. So he performs his biannual “rite of spring,” digging his tubers up, laying the clusters out on a tarp and cutting them apart. After letting them harden for two days, he replants the best of them, saving some to share with a few very lucky friends.
