With clear golden leaves that usually fall around Veteran’s Day, maidenhair trees (ginkgo biloba) are an essential component of the Memorial. Joining them in an urban “grove” around the central flame and fountain are pond cypress trees (taxodium ascendens), as well as hedges and fragrant plants.
“Both the ginkgo and cypress trees represent survival under difficult circumstances,” said Michael Vergason, Founder and Principal, Michael Vergason Landscape Architects, Ltd., which developed the Memorial concept and landscape design. “Their adaptability through the ages, as well as their ability to withstand tough urban conditions were primary considerations in selecting them for the Memorial.”
In designing the Memorial grove of 69 ginkgo and 23 cypress trees, Vergason took a close look at the practical factors as well. Since the Memorial rests on top of the I-395 tunnel corridors with a major highway passing underneath, about 115,000 cubic feet of enriched soil was be brought to the site to support the trees and other plants. The soil is three to seven feet thick, and watered with an underground drip irrigation system. While cypress trees can live under dry conditions, they prefer moister soil than the ginkgos. Therefore, the grove’s soil foundation includes a damper area for the cypresses, with more drainage to dry the soil under the ginkgos.
The pavement for the plaza is carefully suspended over the soil in order to minimize compaction and promote the uniform growth of the trees. In addition, stone pavers were placed among the trees, giving visitors an opportunity to wander through the plantings.
“The grove sets the stage for the visitor’s experience,” Vergason said. “The trees’ overhead canopy create a sense of ceiling, while the dappled light through the leaves and the cooling effect of the plants contribute to both physical and psychological comfort.”
The urban grove – which makes up more than two-thirds of the 2.4-acre triangular site – includes clipped evergreen hedges that parallel the laminated glass panels whose inscribed words and illustrations tell the story of disabled American veterans. A lower level of plantings, including fragrant shrubs, are also incorporated into the site, helping to block visitors’ views of the highway to the south.
But it is the ginkgo and cypress trees that will stand out in the site’s landscape design. The ginkgos were transported from Halka Nurseries in New Jersey, whose trees are also planted at the 9/11 Memorial at Ground Zero in New York City. The pond cypresses were brought from a nursery in Oklahoma City. The trees will grow to an estimated 40 to 50 feet in height over the next few decades.
“Today, ginkgos are also associated with human health and memory,” Vergason added. “Those are very appropriate qualities for trees featured at the Memorial grove. With the cypress and other plantings, the ginkgos will bring a sense of peace and renewal to this very special site.”