Not even good taste, it might seem, can rescue certain tools for the sophisticated gardener. Plastic pots. Impatiens. Perhaps, above all, the lowly marigold.

It can appear fake—splashy and eager to please, with nothing to say—until you get a snoot full of its garbagey spice smell. Certainly anyone who studied garden design in the last 50 years learned to avoid the marigold like the plague. It was considered too easy to grow, too common. Something to stick in a gas-station island in a mindless effort to enhance curb appeal.

Well, not so fast.

Venture through the gates of the walled garden at the Untermyer Gardens Conservancy in Yonkers, N.Y., this summer and you'll encounter hundreds and hundreds of marigolds—not apologizing for themselves, either, but planted in bold sculptural mounds punctuated by erect Japanese hollies. Beds averaging 8-feet wide line the garden's canals and travel around the mosaic reflecting pools. Given the Indo-Persian feeling of this design, it's almost like stepping into an ancient Indian miniature painting.

So who changed the marigold paradigm? A new generation of gardeners who champion all plants—particularly those that are strong, hardy and don't need a lot of chemicals to thrive. People like European gardening rock star Piet Oudolf, who glorified Joe Pye weed in New York's High Line project, and Rick Darke, recognized globally as an expert on grasses, who uses such plants in his naturalistic settings.

"The plants that are still around after all these years are the best of the best—that's why they're here," said Mr. Darke, who loves marigolds not only because his mother and grandmother grew them, but because their strong scent keeps predatory insects away.

Still, Stephen Byrns, chairman of the board of the Untermeyer Gardens Conservancy, was thrown when horticulturist Timothy Tilghman and pro-bono adviser Marco Polo Stufano walked into his office and told him they planned to cast marigolds as the stars of the big summer display. "I had to bite my tongue. I thought that everything we were doing would be uber-sophisticated, and here Timothy and Marco were suggesting something so pedestrian," said the architect, who apparently hadn't gotten the memo on the new-new gardening style.
He had reason to be concerned. After almost 70 years of neglect, and attacks by vandals and invasive weeds, the walled garden—characterized by intersecting waterways, sculpture and incredible plantings—had only recently reclaimed its former glory, thanks to a project put together by the Conservancy and the City of Yonkers to redo the entire 43-acre estate. People were visiting again and Mr. Byrns didn't want to undo progress. "But Timothy and Marco were the experts, so I thought, what the heck," he said.

Turns out that Messrs. Tilghman and Stufano knew exactly what they were doing. "Marigolds are important to Latin, Indian and Eastern cultures," says Mr. Tilghman. The duo particularly liked the idea of using them for a public garden in multi-culti Yonkers.

Recontextualizing such a devalued flower took planning, however. Mr. Tilghman and his gardener, Jessica Norman, chose 13 different marigold varieties such as Janie, Inca II, Discovery and Cresta to get a range of colors, heights and bloom sizes, and planted 1,500 along the canals, in yellows, golds, reds and oranges. When you mass them, said Mr. Tilghman, it gives them greater importance. A taller white variety, French Vanilla, planted down the middle of each bed, makes the whole scheme sparkle.
While the snooty perennial look has been far trendier in recent years, annuals like marigolds have their advantages. Come August, perennials typically withdraw their color to survive the heat while annuals are just coming into show, Mr. Tilghman said. Consider the rose garden: lovely in early summer, but soon the blooms are gone and all you see are thorned canes that look like rebar. "The dainty marigolds we put in this spring are now proudly displaying raucous color," he added, "when the rest of the garden is trying to go solid green."
The key to using annuals creatively, said Mr. Stufano—respected for transforming Wave Hill Garden, in the Bronx, from a sad mess into an arresting jewel—is to forget fads. Train yourself to just look at the plant's essential qualities, its texture, form, height and color, without letting the chicness factor (or the taint of that gas-station island) seep into your brain. He often used ordinary plants like marigolds and thistles in unusual ways at Wave Hill.
"There is nothing too common," he said. "You have to look at a plant with fresh eyes. What is it really about? What can it do for me? I tell people to think of flowers as a great big box of Crayola crayons," he added. "See what you have. Don't rule anything out."