On a winter day, the courtyard of the Gardner Museum is the most beautiful spot in Boston. This formal indoor garden of flowers interspersed with ancient Greco-Roman sculptures is surrounded by four stories of stone columns and balconies plucked from Europe more than 100 years ago by Isabella Stewart Gardner. The fabulously wealthy diva then capped her Venetian palazzo-style museum with a then-revolutionary glass roof to create a year-round Mediterranean garden for visitors.
For the past two years, landscape architect Patrick Chasse has been ''deliciously" delving into archives and doing ''subtle tweaking" to return the iconic courtyard closer to Gardner's version. His appointment last week as the museum's first ''curator of landscape" formalizes his role and elevates the horticultural element of a museum created by an audacious connoisseur who considered gardening another branch of the arts.
''The Gardner Museum is a uniquely visual and aesthetic museum combining all of the arts, including fine art, music, and horticulture," said director Anne Hawley. Noting that the museum's formal music program was created after the benefactor's death, she added, ''We hope Patrick's addition to our wonderful team of curators will have an equally lasting effect on the museum, and the visibility and importance of the horticultural arts."
Chasse will deliver his first lecture as a Gardner curator, ''Gardens and the Mind's Eye," Saturday at 1:30 p.m. at the museum. The event will also mark the debut of a new visitor's guide to the courtyard describing its botanical and horticultural treasures and containing some of the old photographs that helped guide Chasse. For instance, Chinese garden seats shaped like porcelain barrels were returned to the garden based on one of the photos.
''[The photographs] showed that the courtyard had more shrubbery that made it feel like a garden as you walked into it," said Chasse.
Of course, the courtyard has not been open to visitors at least since 1924, when Gardner died. Chasse said he would love to open it for special events ''if it reaches the point where it's stable enough. It's on my wish list -- but a long way out. She had wonderful private parties in the courtyard with orange Japanese lanterns," added Chasse, with a touch of yearning. ''A friend of mine who is in his 80s has a description from his father's memoirs of attending one."
The horticultural exhibit in the courtyard changes nine times a year, a practice that will continue, with the current yellow jasmine trees, white azaleas, and jade trees and cyclamen giving way in March to cineraria, calla lilies, and orange trees from the museum greenhouses. The famous hanging nasturtiums in April are followed by hydrangeas in May, delphiniums in June, fuchsia trees in July, campanula in August, and then a big fall chrysanthemum show, and finally the much-loved Christmas display.
It's a garden that anyone would envy, always filled with perfect flowers.
But it has a dirty little secret: The courtyard is not terribly hospitable to plants. Though it looks aglow with natural light to the visitor, most plants find it too shady. And the ground cover of baby's tears needs continual patching because of poor drainage. Chasse is introducing mosses. ''It's a little swampy. Like a terrarium," he confided.
Many plants must be rotated, as they commonly are in office buildings. Some have understudies in the greenhouse that take turns performing in the courtyard, explained Chasse. ''It's like a stage set. A Metropolitan Opera-type of stage set. And [head gardener] Stan Kozak is the stage master extraordinaire."
Old photos also showed palm trees going up to the second balcony. ''As the palms died, they were not replaced, leaving a more simplified display of just potted plants," said Chasse. But rather than reintroduce in-ground palm trees, he has added potted fish tail palms to the corners because they provide height but are lightweight and easily moved when they need a vacation.
Chasse would also like to ''tweak" the Monk's Garden, a shady outside yard installed by Gardner and open to the public during the warmer months. He is considering staging outdoor exhibits of garden sculpture and ornaments there.
A museum addition is planned for 2011 and one of Chasse's most important jobs will be to work with architect Renzo Piano designing the surroundings for the new wing, perhaps with spaces for changing outdoor ''galleries" of plants and sculpture that could also be viewed from inside. The area in question is currently inhabited by trees, parking lots, and staging space, ''but they're not sacred like the courtyard or the Monk's garden because they were built after Isabella died," said Chasse.
''Curator of landscapes" is a recent title in museum work, used mostly by historic houses and their gardens, such as Winterthur, a leading decorative arts museum and naturalistic estate garden in Delaware. Several years ago, Historic New England (formerly SPNEA) created such a post for its many historic properties. Chris Patzke is the new occupant of that position.
While Kozak does the technical planning as head gardener, Chasse explained, ''I will be dealing more with design, landscape history, interpretation, and educational programs related to horticulture."
Based on Mount Desert Island in Maine, Chasse also maintains a studio in the Brickbottom Building in Somerville. A graduate of the Harvard School of Design, he has taught there and at the Radcliffe Seminars Program, now renamed the Landscape Institute. The garden historian has recently completed an Ottoman garden reconstruction in Istanbul and led last year's successful efforts to purchase and preserve Garland Farm on Mount Desert Island, the last home and garden of Beatrix Farrand (1872-1959), America's first woman landscape architect.
''My firm is just me basically, spread all over the map," said Chasse, who has a waiting list of clients.
Isabella Stewart Gardner in her lifetime maintained the museum's greenhouses at her famous 40-acre garden in Chestnut Hill, which was called Green Hill. That's long gone, and today Kozak and his staff of six use 6,000 square feet of greenhouse space behind the museum, plus a 12,000-square-foot greenhouse on the Hunnewell Estate in Wellesley. That's where the museum's best-loved horticultural tradition, the 20-foot cascading vines of orange nasturtiums, are grown (horizontally) before being hung in the courtyard each year on April 14, Gardner's birthday.
In another floral tradition, violets are displayed in season in a silver cup under ''Christ Carrying the Cross" by the school of Giovanni Bellini, as specified by the Grande Dame.
But there are limits to historic fidelity, even at Mrs. Gardner's museum. ''She put pots of flowers in the Greek sarcophagus in the courtyard, using it as a cache pot!" said Chasse, chuckling.
''If we did that today," added Kozak, ''we'd make the conservation people very unhappy."
Only Isabella could do exactly as she wished.
Tickets for Chasse's lecture are $7 for members, $15 for nonmembers, $11 for seniors, and free for students. They can be reserved by calling TicketWeb at 866-468-7619 or on line at gardnermuseum.org.