Rare Irish orchid discovered in Trinity College after lawn mowing is halted

Orchid which requires ‘perfect set of circumstances’ grew when mowing stopped

A rare Irish orchid has been discovered in the Front Square of Trinity College Dublin after the university stopped cutting the grass on a number of its formal lawns to attract pollinating insects as part of an international initiative.

The broad-leaved helleborine was spotted in the lawns immediately inside the front arch of the college by Prof Jenny McElwain, Trinity’s chair of botany, and has since grown to about two feet tall following a decision not to resume mowing.

More usually found in woodlands, the wild plant has tiny purple flowers around 10 times smaller than those on a cultivated tropical orchid. There are around 16 to 20 flower heads per plant. It has been identified throughout the country, but usually only a single plant is found. However, three plants have sprung since mowing stopped in Trinity under the No Mow May initiative.

“This is super exciting, it is a rare native Irish orchid,” Prof McElwain said. “If you looked you would find it in most counties in Ireland but you’d probably only find one, and it would pop up so infrequently. It might pop up once and you wouldn’t see it again for 10 years, and three of them have popped up in the lawn.”


She said one of the reasons for the rarity of the helleborine is that it requires very specific conditions to grow.

“Like all orchids it can’t germinate unless it has a fungal partner. This one needs a perfect set of circumstances. If it finds the exact right fungal partner it forms fungi around its roots. It’s most likely that this little orchid that’s popped up is connected by threads of fungus to the birch tree it’s under,” she added.

“I think it’s amazing that here, in Front Square, there is really complex biology happening underground. It had probably been happening forever underground and we never let this orchid come up because we always mowed.”

The orchid seeds may have been recently transported to Trinity on the feet or wings of birds, but could also have been “lying in wait” for decades waiting for a chance to grow, Prof McElwain said.

The lawns inside the front gate have never been treated with weed killers or feeds, with regular mowing the only intervention.

“They have never had nitrogen added and over four to five decades the diversity has quietly been increasing and increasing, so when we finally stopped mowing in May the diversity came out through more than 35 species. The orchid has just popped up because the conditions are perfect, the grass, which grows like a brute, hasn’t swamped it.”

The university, which two years ago planted a wild flower meadow at its College Green entrance, is currently considering its options for looking after the orchid lawns, but it is likely to opt for “traditional hay meadow management”, Prof McElwain said. This will involve mowing from August to April.

“If we keep up that management practice what will happen is the seeds will fall in the soil, they’ll find their fungal partner hopefully and, fingers crossed, we might see more orchids next year. Then over time we could get a really fabulous show of orchids.”

Olivia Kelly

Olivia Kelly

Olivia Kelly is Dublin Editor of The Irish Times