The stretch of 14th Street just west of Seventh Avenue is better known for its 99-cent stores than for its chic quotient. But Olivier Giugni, a floral designer who counts Madonna and Julia Roberts among his clients, has never been one to be thrown by conventionality. Earlier this year, Mr. Giugni, who 10 years ago opened the Upper East Side’s L’Olivier Floral Atelier, chose this spot to open L’Olivier Downtown, a sleek shop with an enviably large garden that’s closer in feel to a Chelsea art space than a neighborhood florist.

The narrow store, which Mr. Giugni likes to call a “floral gallery,” sports a modern design, with a polished cement floor, recessed track lighting, and a long granite counter. Lining the walls are enormous black-and-white photographs of misty Parisian gardens. And yes, there are flowers for sale, too: white orchids planted among polished black stones, bright-colored bouquets of dahlias and coxcombs and calla lilies (one is slyly arranged to lie sideways in a glass vase, as if lounging in a bath). A free-form bouquet of mint with red flowers rests on the counter near a tall, striking collection of green mums in a hand-blown green vase. (Most arrangements range in price from $85 to $250).

“Most people say, mums?” said Mr. Giugni, 45, making a face. “But I think they’re divine.” He has made a career for himself challenging people’s floral expectations by creating artful, almost sculptural arrangements. He wraps thick green leaves around containers, spirals stems inside glass vases so they are as much a part of the arrangement as the flowers themselves, and mixes roses with herbs such as rosemary, bay leaves, or red basil.

In Brignoles, the small town in Provence where he grew up, Mr. Giugni loved to help his grandmother in her garden. “My parents had a second home in the country, and every couple of days when we were there, I would beg my father to take me home to water. All the other boys were playing soccer or whatever, and I just wanted to get back to the garden.”

But such a devotion as a child didn’t immediately translate to a career. “Twenty years ago, you weren’t a floral designer; you were a florist, a second-class job,” he said. After several years in retail, he found himself returning to his first interest. In 1980, he interviewed with the fashion designer Pierre Cardin, who was looking for a florist for Maxim’s, his chic Parisian restaurant. “He sat behind this big desk, wearing those big glasses. I was so scared. He said, ‘Do you have a diploma?’ And I said, ‘No.’ Do you speak English?’ ‘No.’ And I thought, ‘It’s over.’ Then he said, ‘You’re hired.'”

In 1986, Mr. Giugni moved to New York City to open Les Fleurs de Maxim’s on Madison Avenue (he eventually did learn English). Eight years later, he struck out on his own, opening L’Olivier Floral Atelier in a brownstone on East 76th Street.

But he longed for a retail space with a garden that he could design with Provence in mind. The 14th Street space gives him ample opportunity. Just outside the back door is a deck with a simple wood pergola covered by plexiglass; for about $2,500, the garden space can be rented out for the night. (One enterprising man already rented it for a dinner to propose to his girlfriend.)

Beyond the deck lies a lush urban oasis, with cypress trees and scarlet bougainvillea, vines climbing up the walls. A sinuous, S-curved love seat occupies a central spot ($4,900), and containers of silky ponytail grass ($80) sit near yucca plants and red banana trees in ceramic pots ($525-$750). Mr. Giugni also offers Provencestyle garden containers, perfect for terrace gardening; they hold everything from rose bushes and rosemary to boxwood petunias and moss ($145-$295). French garden tables feature colorful tops made of lava stone, in shimmering periwinkle and seafoam green ($1,000-$1,500). “You need color in the garden,” Mr. Giugni said firmly. “It is important to think of what it will look like when all the summer flowers are gone.”

Mr. Giugni advised that those who are not lucky enough to have outdoor space consider ways to bring the garden indoors. If the lighting is good, a ficus tree is easy to take care of, and philodendrons and cactus are low-maintenance, of course, Mr. Giugni said. One of his signature arrangements is an orchid garden with moss, bamboo, and small polished stones ($175), a tiny garden in itself that could serve as a sleek accent in most apartments. But never mistake a plant for an accessory: “People have to realize that a plant is a real plant; it’s not plastic, they need care, water, and sunlight,” he said. “Take care of it, and it will respond.”

With fall almost upon us, Mr. Giugni spoke of his favorite autumnal arrangements, such as sunflowers with rosemary, dill, and bay leaves. “Scented geraniums, they are also very beautiful, very fall,” he said. “And then you have all those wonderful flowering branches, such as plum, maple, and pear, blooming in yellows and orange.”

When asked his advice about bringing an arrangement to someone’s house, Mr. Giugni said white and green flowers are always a safe option. “They go with everything.” Then he reconsidered: “Or buy what you like; don’t try to imagine what your friend prefers. Do something that will please yourself.” It’s a philosophy that’s served him well for years.