The centerpiece and largest single element of Longwood Reimagined—a 32,000-sq.-ft. glasshouse designed by WEISS/MANFREDI, with gardens, pools, and fountains designed by Reed Hilderbrand—now has a fully constructed steel frame and is in the process of having nearly 2,000 glass panels installed.
Longwood Reimagined: A New Garden Experience will expand the public spaces of the central grounds of Longwood Gardens and connect them from east to west, offering a newly unified but continually varied journey from lush formal gardens to views over the open meadows of Pennsylvania’s Brandywine Valley.
Longwood’s Cascade Garden, the only extant design in North America by the great Brazilian landscape architect Roberto Burle Marx, is being relocated to an all-new, 3,800-square-foot glass house of its own, a jewel box where the tropical plantings will thrive at the heart of the conservatory ensemble.
A new outdoor Bonsai Courtyard, built alongside the West Conservatory, will exhibit one of the most outstanding collections of bonsai in the country. Other elements of the Longwood Reimagined project include construction of a new education and administration building with a state-of-the-art library and classrooms; renewal of the beloved Waterlily Court designed by Sir Peter Shepheard (1913-2002); and the eventual relocation of six historic Lord & Burnham glass houses from the early 20th century, which will be used for year-round garden displays.
Sustainable Design Elements
The West Conservatory offers a combination of passive and tempering strategies. Ten earth ducts—three feet in diameter, 250 feet long, and buried outside the conservatory—provide year-round passive tempering of fresh air in the conservatory. The tempered air is introduced to the space at the pedestrian pathway to provide passive thermal comfort for occupants and visitors.
This design allows the building to solely use natural ventilation rather than relying on mechanical cooling during warm months. Based on historic precedent and refined via advanced thermal conditioning modeling, the West Conservatory incorporates 10-ft.-tall operable vertical façade openings along the building’s entire perimeter. Outside air entering through these vertical openings flushes out heat buildup, with hotter air rising and escaping through the roof openings, which comprise 15-20% of the overhead surface area.
Additionally, an automated shading system is deployed to reduce solar heat gain during the hottest days of the summer. During cold months, the shading system also acts as a thermal blanket, operating during evening hours to trap heat inside and reduce radiative heat loss.
Longwood Gardens, renowned for its fountains, extends and reinterprets that tradition as part of Longwood Reimagined. Set on an immense plane of water, the West Conservatory welcomes guests into a floating garden of planted islands, canals, and low fountains designed by Hilderbrand. Underpinning this experience of water is a water conservation system that collects stormwater from the roofs of the West Conservatory and education and administration building and captures the overflow from the Gardens’ exterior water features. Water collected from these systems will be stored in large underground tanks and later recirculated through the water features and portions of the restrooms.
The garden is inspired by Mediterranean-climate ecosystems, which are known for hot, dry summers and cool, wet winters, and the regions’ historic traditions of designing thoughtful, expressive water-wise gardens.
Spaces Designed for Preservation And Purpose
Other elements of the Longwood Reimagined project well underway include the new education and administration building, which has nearly completed exterior construction, as well as the new restaurant and event spaces. This spring, Longwood will begin construction of a custom-designed conservatory to preserve the design of Burle Marx’s only extant garden in North America. The Cascade Garden represents the first time a historic garden has ever been relocated and reconstructed.
The garden by Burle Marx, first developed for Longwood in a retrofitted conservatory building in 1992, will now have a new jewel box-like glass house allowing it to thrive for many decades to come.