Flower’s weather eye on rainfall
WALKING around the newly-landscaped back garden of a family member a few days ago, I noticed something interesting. The lawn had recently been churned up to accommodate a new shed and out of the muddy chaos the dormant seeds of a delicate flower had spotted an opportunity to flourish.
Boasting five orange and purple petals surrounding a centre of protruded yellow clumps of pollen on extended hairy stalks, the scarlet pimpernel is a fascinating flower. Considered a weed on agricultural land because it is toxic to livestock if ingested, nowadays we are more likely to spot it on strips of wasteland, roadside verges or coastal cliffs.
Researchers have found the flower’s toxicity increases and declines with summer precipitation. And that is not the only way in which it mirrors the weather.
It has long been seen as an important weather predictor because it closes up when the pressure drops – a trait that gave rise to its nicknames, ‘shepherd’s weatherglass’ and ‘old man’s weather vane’, and the saying: ‘Pimpernel, pimpernel, tell me true, whether the weather be fine or no.’ Other commonplace flowers also warn us of approaching foul weather. The humble bindweed, for example, scourge of allotments across the country, closes up its white trumpetshaped flowers when rain approaches. As do, marigolds, daisies and dandelions. It is thought this may be an evolutionary response that ensures its pollen stays dry during downpours.
The forecasting flowers will certainly be keeping their heads down this weekend as unsettled weather blows in. Heavy rain in the North West, thunderstorms in the South and drizzle and squalls of wind in between it all.
The Met Office says the risk of heavy rainfall will persist next week. Although, with rivers running dry and reservoir levels critically low, I’m not sure that risk is the correct word to use as, after the long dry spell, even the rain-wary pimpernels might appreciate a soaking.