A Mable Ringling rose at the Ringling estate in Sarasota, Fla. (Judy Wells/For The Washington Post)

Before ground was broken for their Venetian-style Sarasota mansion, Ca’ d’Zan, before all the paintings, tapestries and sculpture that would form the collection of the John and Mable Ringling Museum of Art were bought, Mable Ringling started her rose garden. The Italianate wagon wheel of heady aromatic roses that was completed in 1913 turns 100 this month, making it the oldest tended rose garden in Florida.

John Ringling was a tall, blunt, all-business lover of excitement and the grandiose, perfect traits for a circus magnate. His Ohio farm girl wife was a pretty, petite and gracious lover of flowers, who was also an avid reader and a quick and lifelong learner. The couple traveled throughout Europe. While John scouted new acts for the family’s “Greatest Show on Earth,” Mable spent her time in museums honing her taste. Together they bought what pleased them, especially in Italy.

Details: Sarasota, Fla.

Mable decorated all their homes — in addition to Ca’ d’Zan, there was a 100-acre estate in Alpine, N.J., now part of Palisades Interstate Park; 636 Fifth Ave., now Rockefeller Center; a property in Chicago; and the neo-classical Worcester Home on Bird Key, part of a chain of barrier islands between mainland Sarasota and the Gulf of Mexico. The Ringlings also owned 100,000 acres in Oklahoma and Montana.

They began wintering in Sarasota in 1911. When working with architects and craftsmen, Mable was as determined as her husband to have it her way. She must have been, to envision a formal rose garden in the 20-acre jungle of mangrove swamp, rattlesnakes, water moccasins and alligators along Sarasota Bay that they selected for their winter estate.

“We have records of her working wearing a gun on her hip and high boots,” said Ron McCarty, curator of Ca’ d’Zan for 32 years. “She was quite a woman.”

Mable hated snakes, but they weren’t going to stop progress on her rose garden. There was nothing like it in the Sarasota of those days, a quiet enclave of 800 souls when the Ringlings arrived.

Not that the Ringlings and the Florida land boom allowed it to stay that way for long. John became the area’s largest landowner and built the causeway from Sarasota to St. Armands, Longboat, Lido and Bird keys, which he then developed. After creating the John and Mable Ringling Museum of Art, he was instrumental in founding what has become the Ringling College of Art and Design.

Mable was elected first president of the first Sarasota garden club, the Founders Circle, and strongly supported beautifying the city growing around their winter home. She was elected president of the Sarasota Woman’s Club a year later. She commissioned the New York architect responsible for the exterior of the Metropolitan Museum of Art to design their art museum in Sarasota.

The Ringlings loved entertaining. It was nothing for Mable to hold concerts or tea parties for 500 at Ca’ d’Zan (which means House of John in Venetian dialect), their 56-room, 36,000-square-foot mansion. They threw picnic parties for the town, carting hundreds of children and their parents to Lido Beach for food and games.

Her other garden, dubbed the Secret Garden, grew from “onesies and twosies,” specimen plants and cuttings brought to her by friends. Mable, John and his sister, Ida, are buried in a quiet annex.

Today the grounds are still filled with visitors and the ever-growing 13 banyan trees that the Ringlings brought in. The two retired circus chimps and a gorilla that Mable’s nieces and nephews delighted in letting loose are gone. So are Mable’s dogs, macaws and cockatoos. The Ringling estate is run by Florida State University, and for the past seven years the roses have been tended under the watchful eye of ornamental horticulturist and curator Loretta Bestpitch and a cadre of loyal volunteers.

The original garden was a bit smaller than the current one, and none of the rose bushes planted by Mable have survived, but replacements have been selected from hybrid perpetuals, China tea roses, hybrid musk and other varieties available during that era. “Always in the helter-skelter color pattern like she had it,” Bestpitch said.

There are 317 named varieties among the 1,200 rose bushes. They range from small Red Home Runs to Old Timers with blooms as large as one’s head.

Now beginning to emerge from major cutbacks made during January and February, the roses will reach their peak by Mable’s birthday, March 14, and maintain it into April, although many bloom year-round.

“Full bloom will be dazzling,” Bestpitch said, adding that the scent will be, too.

Museums have guards, but how about these rose bushes?

“My red flag goes up when I hear, ‘You take this one and I’ll get that one,’ ” Bestpitch said. “Usually they’re taking pictures, but it has happened.”

Not far from Mable’s roses grow the epiphytes — air plants — at Marie Selby Botanical Gardens.

The Selbys, Marie and Bill, arrived in Sarasota a few years earlier than the Ringlings and had as much money — think mining and oil, as in Texaco — but kept a much lower profile. He was a hunter, fisherman and rancher. Marie was a devoted gardener and, like Mable, a charter member of the Founders Circle. She, too, had a rose garden.

Their home, however, was much simpler, a two-story Spanish-style built on seven acres bought in 1921. The Selbys also had a 3,000-acre ranch near Sarasota where they raised purebred Angus cattle.

Bill established the Selby Foundation, supporting education, the arts, youths, libraries, health services and the elderly, a year before his death in 1956. Marie continued living in their home; she died in 1971, leaving her property to the community as a botanical garden. After consultation with the New York Botanical Garden, the new board decided to specialize in epiphytic plants.

Good choice. Of the 200-plus botanical gardens in the United States, only one, the Selby, concentrates on epiphytes, plants that grow on another plant without taking sustenance from it. The Spanish moss draping trees in the South isn’t a moss but an epiphyte, as are a large number of orchids.

Most visitors begin with the Tropical Conservatory, oohing and aahing their way through the brilliant orchids and eye-catching bromeliads. It and seven other greenhouses hold more than 20,000 plants. Thousands more are outside on the grounds with its huge banyan trees, koi pond and shady paths. Few exit through the Garden Store without being tempted to take home an orchid.

To see Mother Nature’s natural gardens, head across Mr. Ringling’s causeway to Lido Beach, where you can rent a kayak and glide through cathedrals of mangrove tunnels.

Just don’t forget to smell the roses first.

Wells is a freelance travel writer who blogs at www.travelonthelevel.blogspot.com.