Climate change is not rhubarb and it certainly is affecting the health of the plant’s crop, with milder weather this year forecast to see yields fall by more than a third, says one of the region’s leading growers.
Rhubarb is a native of Siberia and the similar rainy, cold climate here has provided perfect conditions for a particular variety of the plant, Yorkshire Forced Rhubarb, to flourish, specifically in an area between Leeds, Wakefield and Morley known as the Rhubarb Triangle.
But Janet Hulme-Oldroyd, who grows forced rhubarb at Oldroyd’s Farm in Carlton, believes growing conditions are changing due to global warming.
“Early varieties are effected by global warming more than any other as they grow in lower temperatures,” she said. “Last year yields on early varieties were down 25 per cent. This year it looks like being between 25-35 per cent. I blame the poor season on unfavourable growing conditions whilst the root lived outside.”
Forced rhubarb begins life as cuttings taken from a rhubarb plant’s mature crown, two years before harvesting. When strong enough the cuttings are planted in fields to mature, ready for the forcing sheds. In the sheds the plants grow in the warmth and stored carbohydrates in their roots transform into glucose which gives forced rhubarb its bittersweet flavour. But this process is only successful if the plant is subject to the right conditions outside.
Mrs Hulme-Oldroyd, whose great-grandfather started the family business in the 1930s, said: “A root must live outside for two to three summers and grow into a large structure full of energy but we’ve had wet summers and droughts – the lot.
“Long growing periods from early springs to the warmest autumn on record to a plant that needs long periods of dormancy do not allow the plant to make large energy reserves from which the plant will grow when it is taken into the sheds. Not enough stored energy results in lower yields in the warm sheds when we trick them into growth.”
An absence of frost this year has proved a problem, she said.
“Frost is necessary for the forcing process to start. At this time of year we like all the sheds to be full of roots from early to main crop. This year we have only had enough cold to take in the earliest variety.”