Orchids on green roofs – Part 1

Orchids on green roofs are in the spotlight in the UK with the discovery of a single short Green-winged Orchid on a roof in Islington.

Orchids on green roofs
Green-Winged Orchid – Orchis murio on the recycling centre Islington.


 Orchids on Green Roofs – Switzerland

Orchids on green roofs in the UK may be uncommon, however, there are some famous Orchid roofs in Switzerland. The most famous orchid green roof is on the outskirts of Zurich. The Moos Filtration Plant in Wollishofen was ‘rediscovered in the 2000s. The roof, when surveyed, was discovered to represent a traditional Swiss wet hay meadow. Many orchid species were present but the most numerous was Orchis murio. Whilst much of the surrounding landscape has lost its botanical character, the 5 huge roofs hark back to an age when intensive agriculture was not the norm. Built in 1910s, the green roof construction was relatively simple; add gravel for drainage and add local farmland soil. The reason was not then ecological, but intended to keep the water beneath the roof cool in summer. This aimed at preventing the build up of harmful bacteria in the water to be used by the citizen’s of Zurich. The roofs, however, developed into one of the ‘eight wonders of the green roof world’. They home to over 13 species of orchids and range of other wildflowers.

Green Roofs Can Help Restore Biodiversity

This roof shows that it is possible to help meet biodiversity objectives. The EU has a target for restoration across the Union. Many roofs could be created in urban areas to help restore lost habitats in the region. This needs careful thought. London, like Switzerland has been at the forefront in ensuring that biodiversity is a key driver in the delivery of green infrastructure at roof level. All to often though because the green roof is on a building the architectural approach is to buy a off the shelf solution. These solutions are designed to meet the building physics that architects prefer; light weight, simple and with minimal design input. To deliver restoration and replication of habitats at ground level designers like The Green Infrastructure Consultancy in the UK need to be involved at an early stage of the design process.