How yellow rattle can inject new life into Ireland's green spaces

Irish Times

21-06-2025

'Gliográn' means 'little rattler' – a clattery, tinkling thing – and it describes well the sound rippling across a
field full of yellow rattle
in late summer, around August, carried best on a dry day with a light breeze. The soft rattling noise comes from the dried seeds inside their papery bladder-like pods, which shake like tiny maracas. Years ago, a tinkling field told farmers it was time to make hay; they'd listen for the sound as their cue to take out the scythe and start cutting.
Finding a large field full of yellow rattle isn't easy these days – it's often considered a
weed
, especially by farmers on high-yield grassland systems. But just last week I stood in a gently sloping Co
Meath
field filled with this yellow flower, with clover growing beneath, at the new 552-acre Brú na Bóinne National Park in Dowth, in the Boyne Valley. The park, which the State bought for €11 million in 2023, isn't yet open to the public (it will take a few more years). But the process of turning the high-nutrient grasslands into spaces for nature has already begun, led by the new park manager, Maurice Eakin.
Dr Eakin has one goal: to bring life back to these lands. To begin the process, he sowed yellow rattle seeds in parts of the park last November. Often called 'the meadow maker' or 'nature's lawnmower', the yellow rattle is a handsome, striking plant with slender, toothed green leaves and sunlit yellow flowers shaped like snapdragon-style tubular bells clustered at the top of its stem. Above ground, the plant is all charm – a beautiful burst of yellow flowers swaying in the fields, as if butter wouldn't melt. Underground, though, it's quite the vampire and thief.
As a seedling, yellow rattle sends out roots that latch on to those of neighbouring plants, especially grasses, and siphon off their water, minerals and nutrients. This parasitic habit weakens the grasses and slows their growth, and it's particularly effective against dominant grass species such as ryegrass. (This is why many farmers understandably dislike it since ryegrass is rich in energy and protein and is fed to livestock.)
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By winning a war against dominant grasses, yellow rattle opens space for less competitive wildflowers to grow, such as oxeye daisy, buttercup, sweet vernal grass and common knapweed. The result is a diverse meadow with flowers that bloom at different times through the spring and summer, offering a steady supply of nectar and pollen for insects and somewhere to shelter and breed. As the wild plant conservation charity Plantlife says, yellow rattle is the 'single most important plant you need when creating a wildflower meadow'.
Although it was cold and damp when I stood in the field with Dr Eakin, the hoverflies and bumblebees were out in numbers, landing on the yellow flowers in search of sweet nectar. As they moved from plant to plant, the bees brushed against the flowers' male parts and picked up dustings of fine, powdery pollen, each grain carrying the plant's sperm cells. When the bees visited the next flower, some of that pollen rubbed off on to the female part of the plant, fertilising it and allowing it to produce seeds.
Just as the yellow rattle gets up to mischief beneath the soil, some bee species get up to tricks while feeding on its nectar. This sugar-rich liquid is buried deep inside the yellow flower, favouring long-tongued bees such as the garden bee, whose tongue can reach 20mm long. Shorter-tongued bees that arrive on the flower can't reach it, but that doesn't put them off. Instead of entering through the floral opening, they land on the side of the flower where the nectar collects, bite a small hole, and drink their fill. These 'nectar robbers' bypass the flower's reproductive parts, so while they get the sweet stuff, the plant gains nothing in return apart from a dose of its own medicine from one thief to another.
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Dr Eakin says he is delighted with how the yellow rattle transforms the field from ryegrass-dominated grassland into a richer, more diverse meadow. His aim over the next few years is to restore life to this part of Meath, and his use of yellow rattle as a key tool in this process could inspire and guide urban park managers across Ireland. Injecting life into public green spaces – transitioning from mown grass to wildflower meadows – can help reverse insect decline and create healthier, more vibrant spaces for local communities.
The impact of urban meadows can be significant. A study published last year by scientists at Warsaw University found that replacing regularly mowed lawns with wildflower meadows in cities leads to a high concentration of pollinating insects, making these urban meadows as valuable as natural meadows in rural areas.
The outlook for pollinators in Ireland is bleak. Our butterflies are in free fall. Recent data from the National Biodiversity Data Centre reveals staggering, catastrophic declines in their populations between 2008 and 2021: the meadow brown down 86 per cent, the ringlet down 88 per cent, the green-veined white down 87.2 per cent. Like bumblebees, butterflies are homeless and starving, with little hope of recovery unless we urgently restore wildflowers to our landscape.
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In this battle, an gliográn – the yellow rattle – could be one of our most loyal and effective allies.