Longwood Gardens green wave wall longest of all

The famed Longwood Gardens in Kennett Square, Pa., recently unveiled the largest living green wall in North America. Until its dedication in October, the plants on the side of PNC's headquarters at One PNC Plaza, Downtown, held that distinction. What makes Longwood's even more unusual is its curved shape and location -- It's an integral part of the interior of Longwood's East Conservatory Plaza, which has been under construction for the past year.

Designed by famed British landscape architect Kim Wilkie, the 14-foot-high wall covers 4,072 square feet and contains 47,000 plants representing 25 species. It is watered by almost 4,000 feet of irrigation drip lines strategically placed throughout.

Stainless-steel panels hold the plants with coconut coir fiber planting media that was developed by GSky, a leading manufacturer of green wall systems. The system was developed to allow the 3,590 panels to move if necessary.

The undulating wall combines with the plantings to give the impression of a gentle green wave. Among the common plants used are spider plants, mosses, ivies and holly, rabbit's foot, asparagus and maidenhair ferns.

Built into the earth, the green wall is part of a glass-roofed corridor that runs between two rows of lavatories. The walls are naturally lit by domes with etched glass and motion detectors that add supplemental light when needed. Motion-activated faucets help conserve water.

The East Conservatory Plaza also can lay claim to the first terraced lawn in the United States. A special mower hovers over the turf, cutting the flat and curved portions at the same height. The plaza is surrounded by new woodland plantings, including hundreds of new trees and shrubs and a magnificent 200-year-old English yew, planted by Pierre du Pont, that stands guard at the entrance to the conservatory.

Longwood Gardens is the premier U.S. botanical garden, encompassing 1,077 acres that includes meadows, vegetable and flower display gardens, water features, conservatories and woodland areas. The original Longwood property was purchased by a family named Peirce, who bought the land from William Penn and established a working farm.

In 1906, Pierre du Pont purchased the property to save the trees from the sawmill. Mr. DuPont loved fountains and designed many of the ones found on the property. He was inspired by his trips to Italy. Longwood Gardens is also a research facility and has programs for horticultural interns, those seeking master's degrees and professional gardeners. It attracts more than 1 million visitors a year from around the world.