No Mow May gives life to rare orchid

Posted on: 03 July 2023

A rare orchid has appeared on Trinity's campus as an unexpected outcome of its decision to allow wildflowers bloom in the month of May.

Trinity stopped mowing several formal lawns across campus for the month of May as part of the international No Mow May initiative.  This allowed wildflowers like clovers and daisies to bloom and provided food for pollinating insects, which are currently in decline.

As the mowing had stopped, Chair of Botany Professor Jenny McElwain spotted an orchid called a broad-leaved helleborine growing in one of the lawns under a birch tree in Front Square. It occurs across a wide geographic range, but is never very common in any one place.  It can cope with human-made habitats like parks and gardens but is really a woodland plant. 

Their roots have a close association with fungi called ectomycorrhiza – in fact, seeds of this orchid need the fungi to germinate and grow for the first few weeks of its life. Even more intriguing is the fact that the fungal partner of this type of orchid is also a common partner of birch trees. There is most likely a threadlike fungal connection deep underground linking the newly emerged orchids to their birch tree neighbour, and this fascinating underground biology would have gone undiscovered had we continued mowing.

Botanists are not certain how the orchids got to front square in the first place.  Prof McElwain says “The tiny dust like seeds could have been transported by birds or humans or the wind, or possibly these orchids have been simply been lying in wait, dormant in the soil for decades waiting to be given a chance to grow.”

After finding the helleborine orchid, Trinity decided to extend the no mow period through June. During that time, a second orchid species popped up nearby, the beautiful deep purple pyramidal orchid.

A botanical survey of the Front Square lawns at the end of May revealed more than 30 different plant species flowering in the lawns, and still more are emerging every week. Those plant species will have various relationships with other organisms, both below and above ground, including the mycorrhizal fungi, pollinating insects and birds. 

A change in mowing regime is not just about the plants flowering in the lawns, but about supporting whole ecosystems of interacting organisms.  

The emergence of this orchid shows that nature can persist and recover, even in the most highly managed habitats. We just need to give nature the space and time it needs to thrive.

No Mow May is an annual campaign started by Plantlife in the United Kingdom and promoted in Ireland by the All-Ireland Pollinator Plan, which was co-founded by Trinity’s Vice President for Biodiversity and Climate Action, Professor Jane Stout. 

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