One River North, a 16-story apartment tower nearing completion in the River North neighborhood, has drawn attention for its facade’s distinctive “canyon” for the past several weeks.

Now the highly anticipated building is filling that multi-story canyon with trees, bushes and plants, essentially inviting the great outdoors into the building in a way no other structure ever has in Denver.

“Plant material is the soul of the building,” said Kevin Ratner, co-founder and managing partner of The Max Collaborative, which is developing the project.

Normally, when nature pierces the frame of a building and trees and plants take over the interior, it isn’t a good thing. But at One River North, the facade was ripped open by design, making it among the most architecturally distinct buildings in the city’s history.

Denver was an early adapter of green roof ordinances, but One River North isn’t content to wear a green hat. It has ripped its shirt open with a “green facade” with flora that will spill across 10 stories of the building at 3930 Blake St.

To help set the project apart in a region seeing a flood of apartments, Ratner and his team turned to Ma Yansong of Mad Architects, a leading proponent of the “biophilic” school of design.

The canyon and a trail-like walkway start on the north end of the sixth floor, near a small waterfall. They rise horizontally through the ninth floor on the other side, with a stairway bypassing a private area on the eighth floor.

Another branch of the canyon in the middle of the building shoots straight up, winding through private apartments until reaching the rooftop deck and pool area on the 16th floor. In all, more than 13,000 square feet of space has been devoted to open-air amenities.

Although MAD designed the building and its winding canyon, a local firm, Davis Partnership, is deciding what plants will populate the spaces.

The plant palette includes native species, as well as ones that are adaptable to Colorado, with close attention paid to wind exposure, light availability and the various micro-climates as the canyon wound its way through the building, Jeff Stoecklein, a senior landscape architect with Davis Partnership, said during a tour of the structure.

For example, the public spaces on the sixth floor are exposed to the north wind, requiring hardier plants, while those on the seventh floor are more sheltered and comfortable.

“We were brought in to answer the question, is this technically viable,” Stoecklein said.

Ratner said the first renderings he received from MAD included lush trees and greenery better suited to warmer climates. Yansong visited a few times, traveled up into the mountains to get a better sense of the terrain that made Colorado special, and incorporated that into his design.

The plants and trees that will fill the canyon are adapted to grow in local conditions, but not all of them are native. Trees going into the canyon include the Standing Ovation Serviceberry, Ginko Tree, Fastigiata Mugo Pine, Tannenbaum Bosnian Pine, Mint Truffle Bosnian Pine and the Staghorn Sumac.

Aspens are not on the list. Although closely associated with Colorado, the trees send out lateral roots with “suckers” that pop up in unexpected places and they drop lots of leaves in the fall. Arborists also advise against planting them in Front Range zones, a key reason Stoecklein said they were excluded.

The building consists of two parts and the back half of the building is fairly standard as far as apartment design goes. But even there, “green” touches are visible, including little planter boxes showing the apartment numbers. Although the boxes could hold live plants, they will be filled with artificial ones.

A corridor with light pouring through on the two ends connects the two sides. A small lobby will greet visitors as they come in. The ground floor desk was kept small so more services could be pushed up to the sixth floor and closer to the canyon.

The sand-colored canyon echoes Middle Eastern architecture, with its undulating flow recalling designs by Antoni Gaudi in Barcelona. Accommodating all the curves has required a lot of custom work on glass and metal frames, which is another way the building offers a sharp contrast with Denver’s mostly linear designs.

One reference people who have toured the bare canyons have made is to Tatooine, the fictional desert planet in “Star Wars,” Ratner said.

One River North will offer 187 units for lease, ranging from studios to penthouses with landscaped balconies. Rents on affordable units start at $1,739 and go up from there, with the larger and more flourishing penthouses saying “contact us,” according to the building’s website.

About 2,000 people joined an interest list for the building, said Amanda Young, a chief marketing officer with Kairoi Residential, which is in charge of marketing and leasing the building. One River North is scheduled for completion by the end of the year with residents expected start living there in January, Ratner said.