For years, other public gardens have been focused on broadening their appeal with wedding packages, concerts and wine-tastings, interactive displays, tree houses, summer camps, yoga, wellness walks, and birding.
That was never the Barnes way.
"Even heavy-duty gardeners came to the Barnes to see the art, so they've been here, but they haven't been in the arboretum. The art was so consuming," said Nicole Juday, the Barnes' horticulture education coordinator.
Now, the goal is not to host weddings or build tree houses, but to market the arboretum as a beautiful, visitor-friendly place to learn about plants.
"When people think about going to a garden for a day, we'd like them to think of the Barnes, but that is not where we are right now," acknowledged Zminda, who is also the Barnes' executive vice president and chief financial and operating officer.
Until now, most visitors have been students or graduates of the Barnes' small but highly regarded Arboretum School, and other advanced gardeners.
Juday wants to host beginner classes. She's adding workshops such as succulent wreath-making and "Moss is Boss." An eight-week botanical drawing course taps devotees of both horticulture and art.
More design classes may be coming, along with three- or four-week "boot camps" on topics such as ferns, which would give busy people an alternative to committing to the school's rigorous three-year certificate program.
With all this, it's hoped that Laura Leggett Barnes - who was married to the art-collecting Albert for 50 years, founded the Arboretum School in 1940, and devoted herself to Barnes horticulture from 1922 until her death in 1966 - finally gets her due.
As enigmatic as her husband was irascible, Laura Barnes was a significant figure on Philadelphia's horticultural scene in the 20th century. Among her contributions was a school curriculum that integrated science, horticulture, and design.
With a quirkiness reminiscent of her husband's art proclivities, Laura Barnes' displays in the arboretum often grouped examples of one plant genus together so students could compare them, rather than a variety of plants with more aesthetic appeal.
"That's how you understand this particular genus, but the design is a relic of another time," Juday explained. "It's also a big part of the uniqueness of the arboretum. There aren't many places where you see that collecting strategy."
Laura Barnes was not a plant explorer in the tradition of Mary Gibson Henry of the Henry Foundation for Botanical Research in Gladwyne and other contemporaries. She found plants in places such as Kew Gardens in London and the Arnold Arboretum of Harvard University.
And, like her husband, she had strong opinions.
She liked flaky bark and unusual specimens from around the world, but disliked variegated foliage and yellow anything. She collected roses, lilacs, peonies, magnolias, and ferns.
Unlike the art "ensembles" replicated in the new museum, the arboretum has evolved over time.
"Conditions change, the light changes, times change, plants die or are added," Juday said. "The most we can do is keep the character of the collection intact."
And that is the experience today.
With 3,000 plant and tree varieties, the arboretum remains an understated, old-school affair. It has formal gardens, a pond, a restored Paul Philippe Cret-designed teahouse, 30 state champion trees, and a woodland grove with more than 200 of Laura Barnes' beloved ferns.
The fern collection has been restored, and there are new beds for medicinal plants and hostas, which Jacob Thomas, deputy director for living collections, hopes one day will be fully labeled and interpreted with signs. That would be a first for the arboretum.
The school's classrooms, conference room and lab, 10,000 dried plant specimens, and a 2,500-volume archive have moved from the Arboretum House on the property to the more spacious Barnes residence.
The prospect of more visitors pleases Diane Newbury of Chestnut Hill, an Arboretum School graduate and copresident of the Barnes Foundation's Alumni Council.
"It may be hard for people to get away from [thinking] . . . 'We can't go there because we don't have a reservation.' You could never just say, 'Hey, let's go there on Saturday,' " Newbury said. "Now we can."
The relaxed rules are a summer experiment, according to Jan Rothschild, the foundation's senior vice president for communications. "We're trying to figure out what we want to be and who our audience is."
The new audience could include not just plant people, but artists such as Anna Yates Krain, senior conservation assistant at the Conservation Center for Art and Historic Artifacts, who took art appreciation courses at the Barnes a few years ago.
"The arboretum was very beautiful, but during that time, artists were not allowed to go into the garden and paint," she said. "I thought, 'Wow, what a great opportunity they're missing.' "
Like other public gardens, the Barnes allows en plein air painting now, too.
"The Barnes has the opportunity here to continue to cultivate community and creativity through the garden," Krain said. "There is so much potential."