By Nancy Grundahl
Longwood Gardens in southeast Pennsylvania has established the largest green wall in all North America. Located in Kennett Square about 30 miles from Philadelphia, Longwood Gardens is an oasis of landscaped beauty. Built by Pierre du Pont between 1907 and the 1930’s, the gardens were turned over to a foundation in the 1940’s to ensure that the general public would be able to enjoy them for years to come.
The idea for the green wall started as a sketch on a cocktail napkin. Longwood desired a grand new entrance to the East Conservatory Plaza. And, because they handle almost one million visitors a year, there was also a need for more restrooms. The result is a curving structure with 17 restroom pods strung together. The walls consist of 3,590 modular panels mounted on a steel framework. Each panel houses a carefully selected variety of plants, about 47,000 plugs in total. The plants are fed by drip irrigation of water enhanced with liquid fertilizer.
The living walls – which have multiple water benefits – help connect visitors with plants, dampen noise in the area, provide moisture and oxygen to the air, and moderate the temperature of the microenvironment in that area. Green walls are one of the tools used by architects and planners to create more sustainable communities. Depending on the design and whether they are indoors or outdoors, green walls can enhance the water environment by slowing down a significant amount of stormwater runoff, resulting in healthier streams. Green walls can also be a way to reuse grey water, such as wastewater collected from washing and runoff from roofs. The plants can purify the water and the system can reduce overall water consumption.
For more information on the green wall at Longwood Gardens, go to: http://www.longwoodgardens.org/EastConservatoryPlazaPR.html.
About the author: Nancy Grundahl has worked for the Philadelphia office of EPA since the mid-80’s. Nancy believes in looking at environmental problems in a holistic, multi-media way and is a strong advocate of preventing pollution instead of dealing with it after it has been created. Nancy likes to garden and during the growing season brings flowers into the office. Nancy also writes for the EPA “It’s Our Environment” blog.