How to Grow Dahlias? A Ceramist Has Some Advice for You

It’s time to unpack the dahlias, and Frances Palmer finds herself surrounded by 25 sizable cardboard cartons full of tubers that she dug up and then stored last fall in the frost-proof cellar of her barn.

To complete the coals-to-Newcastle scene: Several boxes of new tubers she ordered have just arrived, too. Who could have resisted ordering them, even when already in possession of a massive overwintered inventory?

Not Ms. Palmer, a ceramist based in Weston, Conn., whose art and garden have intertwined and grown together over three decades. Each has informed the other, taking on a bit of its shape and character.

Dahlias to the max — apparently there can be no such thing as too many dahlias. As she put it, “They’re just so joyous.”

The products of her two forms of self-expression have posed for many portraits together, as Ms. Palmer, 66, has cultivated a third creative pursuit: photography. The images fill her popular Instagram account and her 2020 book, “Life in the Studio: Inspiration and Lessons on Creativity.”

Ms. Palmer’s ceramics are highly distinctive, but entirely functional. These vases, dinnerware and serving pieces are meant to be sold, and used. From the start, she wanted to document her designs, and realized she could lend a sense of scale by working in some props. Like flowers in the vases.

“That was really my impetus to start gardening,” she said. Once she did, no flower tugged at her harder than the dahlia.

In her connection to them, Ms. Palmer is in good company among creative women, including Frida Kahlo (who grew them in her garden in Mexico, where dahlias are native, and was frequently pictured wearing them like a crown). Vanessa Bell, a member of the Bloomsbury Group, grew and painted dahlias at Charleston farmhouse in East Sussex, England, and a memorable photograph of the contemporary Japanese artist Yayoi Kusama as a child shows her holding four giant ones.

That’s no surprise, really, considering the flowers’ vivid color palette, sculptural geometry (the shapes include preposterous pompons and balls as well as spiky cactus-like blooms) and size (from less than two inches to almost a foot across).

Although she won’t put a number on it, Ms. Palmer acknowledges growing “hundreds” of dahlia plants a season, each given just enough real estate to accommodate the tomato cage supporting it. The goal: an abundant flower harvest.

“Because my garden functions as a cutting garden, I just use the tomato cages, and they go cheek by jowl,” she said.

The plants fill two large, fenced garden areas: four 16-by-16-foot beds in one space and 30 raised beds of four-by-eight feet or longer atop an old tennis court, where she also keeps several beehives.

And it’s not just dahlias she grows to cut.

“I have all sorts of things happening,” she said, ticking off a flowering cascade from spring bulbs to sweet peas, annual poppies and natives like asters and ironweed (Vernonia) that peak simultaneously with the dahlias. “But the dahlias always get the best — and the most — real estate, and everything else gets pushed in between. It’s quite chaotic.”

Visitors to her annual Garden Conservancy Open Day (this year, it’s on Sept. 30) don’t seem to mind.

Everything appears in delightful excess, unfolding toward “a great crescendo in the garden,” from the time the dahlias get going, by mid-July or so, right through till frost says stop and those cardboard boxes get loaded up again.

So Many Dahlias, So Little Space

Most of us will never try growing “hundreds” of dahlias — even over many seasons. There are almost 11,000 named dahlias on the American Dahlia Society’s composite list of varieties, from 1976 to the present; international groups list even more. The largest source in the United States, Swan Island Dahlias, carries more than 400.

So which ones should we seek out?

It’s a topic that Ms. Palmer, who also recommends Ferncliff Gardens, Old House Gardens and Queen Valley Farm as sources, covers with students at the New York Botanical Garden in the Dauntless Dahlias course she has taught every March and October since 2015.

“Think abstractly versus specifically,” she advises. Consider which colors, shapes and forms you prefer — and what scale.

“Don’t obsess over the names of the dahlias, because if you can’t find them, it’s really irrelevant,” she tells her students as she projects images of outstanding examples. “You can find something that looks kind of along the same lines. If you want a pink cactus dahlia, it doesn’t have to be the particular one that I’m showing you.”

That doesn’t mean she doesn’t have favorites. Pressed to name names, she does: yellow, peony-shaped Meadowburn Old Tweet, for instance, and Juanita, a six-inch-across cactus type in rich red. Also Cafe au Lait, the palest peach or barely pink, which is often used in weddings.

Some are extra-flashy, like Bodacious (big, bright orange petals with yellow undersides), Myrtle’s Brandy (distinctive, reflexed red petals with white tips) and Deuil du Roi Albert (purple tipped in white). Bishop of Llandaff has screaming, semidouble scarlet flowers and dark purple foliage.

The list goes on. She always makes room for flowers of velvety black-red (maybe giant Spartacus or smaller Paul Smith) and “a good orange” (Clyde’s Choice can reach a foot across). Pink (perhaps the massive Otto’s Thrill) and white (Walter Hardisty, another big guy) are also musts. At least one color — yellow, which she once disliked — has grown on her thanks to her relationship with dahlias.

In each hue, she said, she seeks a range of shapes and sometimes shades, “so that when I’m putting them together in arrangement, you’ve got some nice diversity of form and color and size. If you have a little bit of everything, it’s so easy to put together something that looks abundant.”

Homegrown zinnias and marigolds are among the other ingredients in that abundance; so are copper fennel, nasturtiums and even strands of clematis vine.

One simplifying tactic she suggests if you want get started: Shop according to a color or shape theme.

“If you like yellow, just get yellow dahlias that are pompons or decorative or cactus,” she said, “so that you have a variation of shape and form. Even if you decided to just do ball dahlias one year, and only had all different colors or sizes of ball dahlias, you would have a fabulous garden.”

A Grower’s Tips: From Planting and Pinching to Storing

Except in Zones 8 to 10, where they are perennials, dahlias tubers are planted outside like annuals, around tomato-transplant time. Ms. Palmer plants hers in mid-May, around Mother’s Day.

There is no room in a greenhouse or under lights to pot up all of those overwintered tubers for a head start, but new mail-order purchases tend to arrive well before it’s safe to put them outdoors and may dry out if left in their boxes. She pots those up, or at least stashes them in a tray of potting soil.

In May, each tomato cage from her giant collection is called into service, gridded out in the gardens along with a stake or two to reinforce it. Beneath each one, a tuber is planted so that an inch or two of soil covers it. A tag marked with the dahlia’s name is tied onto the cage.

“The most important thing about planting a dahlia tuber is getting your support system in place immediately,” Ms. Palmer said. As the plants grow, she uses biodegradable jute twine for further support, and maybe another stake for the tallest ones. Where cages may look out of place, you can use just bamboo stakes and twine.

Also important: When the first stem pushes up six to 12 inches high, Ms. Palmer pinches the center bud to promote bushiness.

A second pinch, or disbudding, can encourage long stems for cutting. As the plants get ready to produce flowers later on, they form three buds at the end of each branch; pinch off the outer two in each group. Ms. Palmer repeats this as the plants continue to set flowers.

Every couple of weeks throughout the summer, she dilutes fish emulsion with water in a two-gallon sprayer, and “the roses, the tomatoes, the dahlias — everybody gets a spray, all over the garden,” she said.

And on they grow, until the first frost. Ideally, Ms. Palmer waits till a week or two after it blackens the plants, and then cuts them back and digs them out. But sometimes frost comes so late she has to dig before it arrives.

She brushes off clods of soil and spreads the tubers out to cure in the barn for a week or so. Then she cuts the stems to maybe two or three inches long, packs the tubers into her cartons with a wood-shaving material from the farm store labeled as horse bedding, and back they go into the cellar.

Oh, but wait: There’s one more step. Don’t forget to tie the tag on the tuber’s stem before you put it away — if you can keep the exhumed darlings straight, that is.

“And I do try,” Ms. Palmer said. “Although it’s a Kafkaesque exercise to tag the tubers with names after I cure them. Thankfully, I don’t really care at the end of the day.”

Margaret Roach is the creator of the website and podcast A Way to Garden, and a book of the same name.

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