From the 61st floor of Salesforce Tower — that is, from the tippy top — the 360-degree views of San Francisco and the Bay Area are blue with water and often grey with fog, but not very green.

Outside, that is.

Inside, the glass-walled circular space is punctuated by 24 floor-to-ceiling columns of living plants, like half-hour increments around a clock. Employees, clients and visitors lounge around on comfortable chairs, looking out on the cityscape while nestled amidst greenery that would do any jungle proud.

“I’ve always been interested in how plants affect people, the beneficial effects they have on our moods and well-being,” said David Brenner, founding principal and lead designer at S.F.-based Habitat Horticulture.

Brenner and his company worked with Salesforce Tower’s architects to create what is certainly — at 1,070 feet — the highest garden in San Francisco.

It’s safe to say a lot of people will be seeing these horticultural displays. Salesforce founder and co-CEO Marc Benioff opened the tower’s top floor (the Ohana Floor) to the public early in the year, but visiting proved to be so popular that now public visits are limited to tours one Saturday per month, starting Feb. 23. (As of now, reservations are already full through August.)

Brenner, 34, has long held an interest in vertical gardening, and the fact that he was awarded this plum contract may reflect his success at dotting the map with his previous work all over the Bay Area, and beyond.

In fact, after studying horticultural science at Cal Poly San Luis Obispo, where he experimented with methods of building living walls, the San Jose native created his first non-academic project in Tel Aviv. After completing a Birthright Israel tour in 2011, he stayed on for an extra 10 days to build a 9-foot wide vertical garden on an available commercial wall on Shenkin Street, where his cousins own a restaurant.

Before that trip, he long had admired the work of pioneering European botanists, such as Patrick Blanc (credited as the modern inventor of the living wall), and done an apprenticeship at the famous Kew Gardens in London, focusing on epiphytes — plants that grow on trees or other vertical surfaces but are not parasitic.

So when his trip to Israel left him in the mood to give something back, a living wall came to mind.

“I was just starting out and was inspired,” he recalled during an interview at Salesforce in downtown San Francisco.

It was two years after college when Brenner founded Habitat Horticulture, in 2010, while working at a tree and plant nursery in San Francisco.

“I’ve always loved plants, and my thought was that cities, in general, have too much concrete and not enough parks,” he said. “I saw this as the best way to bring the most greenery into the places where people work.”

In 2013, the California Academy of Sciences in Golden Gate Park offered him a platform for his ideas — literally. It was an 18-by-12-foot wall called “the living stage” that put plant life on display in a new way. A wall in a Financial District bank followed, along with a South of Market exterior wall at Foundry Square.

I’ve always been interested in how plants affect people, the beneficial effects they have on our moods and well-being.

“People were skeptical at first, but with these small projects I showed people that it could work,” Brenner said. The company quickly took off, benefitting from the tech boom and massive new building projects in San Francisco and the South Bay.

Cisco, Ideo, Facebook and Symantec are among the companies that now display Brenner’s vertical gardens in their headquarters. His work also graces many residential projects, health care facilities and private homes.

In 2016, Brenner’s firm completed two projects: one at the San Francisco Museum of Modern Art, the other at the Stanford Graduate School of Business. The former, by far his largest project to date, is an exterior wall 150 feet wide and 29 feet high that artfully intermingles 37 different plant species. The pattern of the planting, and its use of different colors and textures, looks like a work of modern art itself.

Habitat Horticulture currently has about 36 employees, plus a “Chief Happiness Officer” — a Siberian husky mix named Romeo whose “mugshot” and title are included on the staff page of the company website.

The benefits of living walls are not hard to sell. On a practical level, they are a way of increasing the presence of nature in urban areas without taking up expensive horizontal square footage. And environmentally speaking, they cool and filter the air, and insulate interiors from extreme temperatures (thus decreasing a building’s energy consumption and carbon emissions).

Moreover, living walls can improve the quality of air by increasing humidity, which helps alleviate common workplace complaints such as dry eyes and fatigue. Also, living walls soften and dampen sound waves through absorption and refraction, thereby reducing echoes in large rooms and muffling distracting noises from the street.

But what the average person notices most when walking into a building designed to include a great number of plants is simply the sense of physical and mental wellbeing one feels in the presence of natural greenery.

It’s something Brenner has observed since he was a student, and now it’s the happy foundation of his life’s work. It keeps him content to live in the city with his wife, Amber, and to spend many a weekend day in his North Beach office designing his next garden (at least until the couple’s first child is born in the spring).

Up on the 61st floor of Salesforce Tower, Brenner engineered systems to integrate vertical gardens with the 24 steel columns that are part of its structure. Completed in September 2018, the Ohana Room includes approximately 25,000 plants (about 1,000 to 1,200 per column) and 800 square feet of garden in wooden planters on the floor. The vines, grasses, ferns, leafy plants and epiphytes differ from column to column, offering astonishing visual variety. (There also are living columns on the private floor below the 61st.)

“The end product is hard not to like,” Brenner said. “What you see is beauty, textures, all these living things. It’s an art form, but it involves framing, plumbing, irrigation, drainage, lighting — all the details that make it look seamless.”

The column gardens are automatically watered, but Habitat Horticulture employees show up to tend the plants when visitors aren’t around — usually between midnight and 4 or 5 a.m. As the plants grow and merge, the foliage requires constant pruning, and, of course, Salesforce officials don’t want to see any fallen leaves on the floor (there aren’t any!).

Yet during the interview, Brenner is eyeing a spot on one column where a few leaves on a green vine are turning a bit yellow, whereas the neighboring magenta coleus is bursting with perfect health.

“One of the ongoing challenges is that, with the garden growing on columns placed around the circumference of a circle, different parts of it receive different amounts and angles of light,” he said “which also changes with the seasons.”

Not surprisingly, Brenner stays on after the interview to attend to it.