The shortlist of infrastructure projects was chosen from 170 entries by judges keen to tease out the best creative ideas for green spaces in the capital. The competition is inspired by New York’s High Line urban park, a former elevated freight rail line.
"Our competition has inspired a shortlist of ideas that range from massive city-wide strategies like using the empty space on top of buses, trams and trains to create mobile gardens to small-scale community projects like miniature urban woodlands in forgotten spaces," said a spokeswoman.
Landscape Institute president Sue Illman said: "The challenge was to go beyond the commonly accepted role of an urban park and engage communities with the benefits of green infrastructure to improve the way we live in our cities.
"The entries speak volumes about a new generation of design talent ready to engage with green urbanism to create beautiful places designed to provide benefits like flood management, urban cooling, green transport links and ecological connectivity."
London mayor environment advisor Matthew Pencharz said: "We are benefiting from the parks that were created in the past and we need to ensure we are planning and designing green spaces that are both beautiful and functional for the next generation to enjoy."
The shortlist includes Green Arteries by Bell Phillips Architects, Spacehub and Aecom, a scheme to transform London’s flyovers into productive green arteries to reduce the heat effect and traffic noise and encourage biodiversity.
Street Orchard by Laura Rowland and Claire Beard consists of miniature orchards around bus shelters and insulated beehives in the trees and sloped sedum roofs. Bus Roots by Wynne James utilises empty roof spaces of bus shelters to create raised gardens.
The shortlisted entries are on display at the Garden Museum and the winners will be announced on 8 October as part of the High Line Symposium from 5 to 8th October.
An online gallery of the shortlist can be seen at http://www.landscapeinstitute.org/events/competitions/highline.php