We’ve got an old bridge over the Fort Point Channel. It’s going to be decorated for the next few years with flowers in boxes. Why is this important?

Let’s place it first. It is the Northern Avenue Bridge connecting Northern Avenue where it passes between the Moakley Courthouse and the Barking Crab in the Seaport District and ends in a parking lot on the edge of the Rose Kennedy Greenway. Built in 1908, the deteriorating bridge no longer carries vehicle traffic, but has been retained for pedestrians. A while back there was a lot of hoopla over restoring the bridge, but that plan went on ice during the recession. The bridge is historic, so people want to save it, but it is low to the water and must swing open to let boats through, a condition that requires oversight and maintenance. When it is restored it may be elevated to allow boats to pass beneath it, but plans are not firm yet.

Meanwhile, The Boston Harbor Association will install 12 substantial custom planters filled with evergreen shrubs, bulbs, grasses, perennials and annuals on the bridge to make it more inviting. The planters should be ready this spring.

It’s a small thing in one way. It’s only a $50,000 project, with funds raised by the Boston Committee of the Garden Club of America, which includes the Garden Club of the Back Bay and the Beacon Hill Garden Club and 12 other clubs in eastern Massachusetts and southern New Hampshire. Michele Hanss, a Chestnut Hill resident, has been the prime mover toward this goal.

The funds will pay for a “horticultural display called the Harbor-Link Gardens [which] will transform the bridge .  .  . with lush, hardy seaside garden plants, horticultural signs, and colored pavement surfacing,”  according to a press release. The gardens are temporary, lasting from three to five years, since the city is eventually expected to restore the bridge, said Vivien Li, executive director of The Boston Harbor Association.

Such beautification, however confined, shows a welcome change in attitude on the part of Boston’s civic and business leaders.

The Boston Harbor Association was started 40 years ago by the League of Women Voters and the Boston Shipping Association to clean Boston Harbor. The women tried to get the men of the financial district and business community interested in bettering the harbor, but got no takers, said Li.

The men are now on board, said Li, with adjacent businesses offering maintenance of the planters and David Warner of Warner Larson Landscape Architects donating his talents in the bridge installation’s design.

It wasn’t that 40 years ago women saw the benefit of clean water and beauty and men couldn’t. One problem was that beauty and cleanliness were believed to be unimportant. Too often they were seen as qualities rich people valued but no one else cared about. It was part of that Boston habit, now thankfully much diminished, that separated Bostonians by class.

More than 20 years ago, a Boston city official told me that Beacon Hill and the West End couldn’t have bricks on Cambridge Street sidewalks because only rich people wanted bricks and pretty spaces. I wondered from what planet he was coming from. I thought that people in all walks of life wanted beauty and felicitous surroundings. Luckily, the reconstruction of Cambridge Street was delayed so long that this city official had moved on to other ventures.

Another change has been in maintenance. A couple of decades ago, when city officials did build something attractive, they didn’t maintain it. And sometimes they still don’t, if City Hall Plaza is any indication

But times are better now. You can bet these boxes will be maintained. People no longer roll their eyes over beauty or maintenance whether it is garden club ladies pushing the effort or a city official.

Science is now on the side of beauty, especially when it comes from plants. “Your Brain On Nature: The Science of Nature’s Influence on Your Health, Happiness and Vitality,” is a new book by authors Eva M. Selhub, M.D. and Alan C. Logan, N.D., both at Massachusetts General Hospital.

Logan said in a telephone interview that gardens influence our health. Research has shown that when humans view gardens or other natural spaces, the areas of the brain associated with emotional stability become more active.

“Your experience with nature ultimately dictates your attitudinal perspective toward the environment itself,” he said.   Moreover, in urban settings proximity to green space is associated with the lowering of perceived stress. Cognition improves too. It’s not surprising, given that over thousands of years humans evolved living in nature.

Downtown Boston’s green space, already plentiful with the Public Garden, the Common, the Commonwealth Avenue Mall and the Esplanade, has been increased with the Greenway, the parks on the north bank of the Charles River and the Harborwalk. Boston is cleaner, especially now that cars are towed on street cleaning days in many neighborhoods in the city. (Of course, a Coloradoan, Dennis Royer, formerly head of public works, had to do that for us, but still.) The greening of the Northern Avenue Bridge may set a standard in beauty and maintenance for the rest of the Seaport District.

“This is small,” said Logan, “but anything helps. If water is around, it’s even better.”