Broad-leaved Helleborine - our fifth orchid
Broad-leaved Helleborine Epipactis helleborine – A new orchid for WWT London Wetland Centre
Guest blog by London Wetland Centre’s Chief Ecologist Richard Bullock
This is a woodland orchid rarely seen in the built up areas of London. However, it is the least rare of the helleborines to be found in the London area, with the best established populations residing in the vicinity of woodlands located on soils comprising clay-with-flints overlying the chalk of the North Downs. It grows in a variety of locations where the soil is not wet and the plant is not usually exposed to full sunlight. Plant establishment at any one location is associated with the presence of specific ecto-mycorrhiza fungi within the soil.
In recent years, more records have been made of this species further in to Central London. The appearance of this orchid at WWT London Wetland Centre highlights the fact that although this species is most often associated with older established woodlands, the plant does, nevertheless, have the ability to colonise new localities where woodland habitat has only become established over the course of a matter of years rather than decades (e.g. secondary woodland) or indeed centuries (e.g. ancient woodland).
The London Wetland Centre plants have become established in a locality comprising a mixture of willows, alders and birches – the tallest trees no older than 16 years of age. Despite the young age of the tree canopy, sufficient shade has developed over the clay-based substratum to provide the necessary conditions for seeds to germinate, and plants to establish and flower. The species was only discovered on site quite by chance in mid December 2011.
The relative lack of frost during the early winter period meant that the green leaves remained intact upon the newly found plants. Two flower spikes containing dehisced (burst open) seed heads in December had clearly been produced in late summer 2011. Returning to the location during the first week of August 2012, two further flowing spikes were evident.
The occurrence of this fifth species* of orchid at the London Wetland Centre demonstrates that importance of green spaces within Greater London.
* the other orchids we have here are Bee, Common spotted, Pyramidal, and Southern Marsh.
