New London ― One might think it hard to achieve peace within 100 feet of bustling Route 32 ― a highway that carries thousands of passengers daily to and from the heart of the city.

But across from Connecticut College’s main entrance on the highway, on a five-acre expanse known as the Caroline Black Garden, a plaque proudly distinguishes it, among three other botanical gardens in the college’s arboretum, as a garden of peace.

Arboretum volunteer Allen Gauthier, pointing out the plaque to a group of 16 who toured the garden on Sunday, said it was “quite an honor,” to receive the designation, which came on May 4, 2001, from the international organization “Gardens for Peace.” That group seeks to promote and achieve world peace “through the universal language of gardens.”

The Caroline Black Garden, also known as the college’s “secret garden,” was started in 1928 by a woman of the same name. She was the botany department’s first chairwoman, and was simultaneously involved with the landscaping for the entire campus, according to the Connecticut College Arboretum website.

With the goal of using it as a teaching tool, Black established the garden with mostly native perennials, which Gauthier said included irises. In almost a century since then, the garden has grown to incorporate much more exotic features, including Japanese maples and stewartia, a flowering tree, along with a Japanese-inspired water garden. In terms of plants, the garden has 226 taxa in total.

According to the website, Black died in 1930, and the college’s board of trustees voted to name the garden in her memory. And though it’s grown significantly since then, Gauthier said it hasn’t lost its original intent, which was to be a teaching device.

“An arboretum is for ― really ― learning. And then disseminating that information,” he said.

Retired Williams School teacher John Sargent, 76, of Quaker Hill, who visits the college’s arboretum three or four times a week, agreed, describing the arboretum as “an environment for constant learning,” and adding that nature has both mental and physical benefits.

As Sargent and others wove through the maze-like pockets of trees, shrubs and flowers and vines that were interspersed with beautiful reds, pinks and purples, Gauthier pointed out some highlights.

He “made note” of a hemlock from a volcanic island, along with conifers and cork trees. Then he showed a towering beech tree whose limbs were thick with crimson leaves. As Gauthier chatted, little was heard of the Route 32 traffic ― more apparent were the sounds of birds and falling water.

One of the last stops Gauthier made before he led tourgoers back through a wooden gate entrance to the garden was at Opuntia cespitosa, more commonly known as the Eastern prickly pear. He said it was not yet in bloom, but is known to have beautiful flowers in June.

With the tour concluded, and Sargent standing back by the entrance to the garden, he reflected on its tranquility and great variety of plants.

“We’re nature lovers for one thing,” he said. “And we like to frequent the same place.”

“This garden is particularly peaceful I think,” Sargent added. “It’s a sanctuary in a city. Like rooms in a container, where you feel away from the usual hubbub.”

Across from the garden, at Winchester Apartments, third-year Connecticut College quantitative economics major Liam Merrill was packing belongings in his car after finishing his last final. He likened the secret garden to the “garden of Eden,” and said he and friends visit it to hang out.

“Yeah, it’s nice,” he added.

d.drainville@theday.com