March 7, 2016

Since February 23 at the Gateway Arch, 113 London Plane trees have arrived, beginning the project of lining the processional allées on either side of the monument. An allée is a tree-lined pathway in a formal garden or park. The pathways are part of the Jefferson National Expansion Memorial’s historic landscape designed by Dan Kiley and Eero Saarinen.

The first trees arrived at the grounds by truck from New Florence, MO. The trees were stored there for two years and cared for by members of the CityArchRiver project design team, while acclimating to the local climate. The trees are currently over 20 feet. tall. The soil around the allées has been designed for the tree roots to expand, ensuring successful growth. Planting of the 800 London Plane trees along allées will continue throughout spring of 2016.

The tree planting project is part of the overall landscape renovation at the Arch. In 2014, crews removed the original Rosehill Ash trees on the grounds, which were threatened by the Emerald Ash Borer. The London Plane – a proven hardy species that is successful in urban areas – replaces the Ash trees to maintain the iconic symmetrical vistas along the allées. Before the CityArchRiver project, the Arch grounds had 1,895 trees. The landscaping component of CityArchRiver doubles the number of trees on the grounds to more than 4,000, adding a variety of local species.