Longwood Gardens/L. Albee

Topping out with a total surface area of 4,072 square feet, the new green wall at the recently opened East Conservatory Plaza of Longwood Gardens, a horticultural center in Kennett Square, Pa., is the longest indoor green wall in North America.

Designed by British landscape architect Kim Wilkie Associates, the green wall features a panel wall system from GSky Plant Systems of Vancouver, British Columbia, Canada, that supports more than 47,000 plants from 25 plant species, the majority of which are varieties of ferns. Its surface area makes the new wall more than 50 percent larger than the next-largest indoor green wall, located at the PNC Bank building in Pittsburgh, which measures 2,380 square feet.

The plants of the Longwood wall are planted in 3,590 panels, which were started at a nursery for 32 weeks before installation, and then were transported to the site in three climate-controlled trucks. Twenty-four irrigation zones and 3,900 linear feet of irrigation drip line maintain the plants.

It is estimated that the wall will provide an annual amount of oxygen equivalent to that produced by 90 14-foot-tall trees and will clean more than 15,000 pounds of dust and toxins from the air per year.

The living wall lines a glass-roofed corridor that forms a spine between two rows of 17 domed underground lavatories of the new East Conservatory Plaza, also designed by Wilkie in collaboration with London-based architect Michaelis Boyd Architects; Princeton, N.J.based Farewell Mills Gatsch Architects; and Philadelphia-based landscape architecture firm Wells Appel. The new plaza acts as an arrival point for conservatory visitors and is structured as five tiered terraces that are meant to appear as steps in the site’s landscape.

To read a more detailed article on the green wall technology employed at Longwood Gardens from the November 2010 issue of ARCHITECT magazine.