Ревеневый треугольник Йоркшира: земля раннего ревеня.

Rhubarb producing area in England

The Rhubarb Triangle is a 9 square miles (23 km2) area of West Yorkshire, England between Wakefield, Morley, and Rothwell famous for producing early forced rhubarb. It includes Kirkhamgate, East Ardsley, Stanley, Lofthouse and Carlton. The Rhubarb Triangle was originally much bigger, covering an area between Leeds, Bradford and Wakefield. From the 1900s to 1930s, the rhubarb industry expanded and at its peak covered an area of about 30 square miles (78 km2). Rhubarb is native to Siberia and thrives in the wet cold winters in Yorkshire. West Yorkshire once produced 90% of the world's winter forced rhubarb from the forcing sheds that were common across the fields there. In 2010, Yorkshire Forced Rhubarb was awarded Protected Designation of Origin (PDO)
status by the European Commission's Protected Food Name scheme after being recommended by Department for Environment, Food and Rural Affairs (Defra).

The cultivation method for forced rhubarb was developed in the early 1800s. The fields were fertilised with large quantities of horse manure and 'night soil' from the nearby urban areas and woollen waste from "mungo and shoddy" mills. The rhubarb plants spend two years out in the fields without being harvested. While in the fields the plants store energy from the sun in their roots as carbohydrates. The roots are subjected to frost before being moved into sheds in November where they are kept in complete darkness. In the sheds the plants begin to grow in the warmth and the stored carbohydrate in the roots is transformed into glucose resulting in forced rhubarb's sour sweet flavour. The sheds are long low buildings which are heated; originally with coal, which was plentiful and relatively cheap in the area, but this has been replaced by diesel. Forced rhubarb grown in the sheds is more tender than that grown outdoors in summer. Without daylight the rhubarb leaves are a green yellow colour, and the stalks, measuring around 2 feet (1 m), are crimson in colour with a smooth texture. Traditionally, the pickers pull the stalks in candlelight as any exposure to strong light will stop the growth. By the end of March the harvest is over and the root stock is totally exhausted and used for compost.

Twelve farmers who farm within the Rhubarb Triangle applied to have the name "Yorkshire forced rhubarb" added to the list of foods and drinks that have their names legally protected by the European Commission's Protected Food Name scheme. The application was successful and the farmers in the Rhubarb Triangleefn|The Rhubarb Triangle's geographical area in EU law is "from Ackworth Moor Top north along the A628 to Featherstone and Pontefract. Then on to the A656 through Castleford. It then goes west along the A63 past Garforth and West Garforth. Head north passing Whitkirk, Manston and on towards the A6120 by Scholes. Follow the A6120 west, round to pass Farsley which then leads south west via the A647 onto the A6177. Pass Dudley Hill to pick up the M606 south. At junction 26 take the M62 south to junction 25 head east along A644 toward Dewsbury, passing Mirfield, to pick up the A638 towards Wakefield. At Wakefield take the A638 south to Ackworth Moor top."

Wakefield Council holds an annual Rhubarb Festival in February, celebrating the area's links and promoting the surviving rhubarb industry. A Farmers' Market, cookery demonstrations, walks and tours of the forcing sheds are among the attractions. In 2005 Wakefield council erected a sculpture depicting a rhubarb plant in Holmfield Park Wakefield. Rhubarb growing and the 'Rhubarb Express' are featured in Wakefield Museum. In 2016 an exhibition of photographs by Martin Parr at The Hepworth Wakefield featured The Rhubarb Triangle series of images, along with a publication. In Frances Brody's 2019 novel The Body on the Train (Piatkus: ) a murdered man's body is found on a rhubarb train from Ardsley, on its arrival at King's Cross. The book's cover illustration features boxes of rhubarb on a platform beside a train.