Is it a fruit? Is it a vegetable? Or is it even a herb? No-one seems to be prepared to commit but it’s quite possible to go along with the theory that wonderful rhubarb is all three. In scientific terms, the large perennial herb rheum rhabarbarum produces vegetable stalks which we know as the fruit, rhubarb. A rhubarb guide ruling in a New York customs court in 1947 defined it as a fruit and certainly that’s how it is usually used.
Rhubarb’s popularity really took off in the 19th century, when new cultivation techniques were developed. As the price of sugar fell, it became easier to soften the tartness of its flesh and so consumption increased, peaking between the two world wars.
Forced rhubarb in the UK
From December to March, dark sheds are used to harvest an especially sweet and tender stalk by candlelight earlier in the year than is possible when growing in a field. This practice is particularly prevalent around Yorkshire but the effect can be recreated by the amateur gardener, using an upturned bucket or bin to exclude light from plants grown in the ground. As a result, fresh stalks are available for a large part of the year in the UK.
The part of the fruit we eat is the stalk, which comes in colours from a deep red through a spectrum which includes dappled light pink to pale green. Some varieties grow small and neat stalks while others can grow up to 1.5 metres long and as thick as an aubergine. It is most often stewed with sugar and used as a preserve and in pies and crumbles. However rhubarb has a long medicinal history as a laxative, starting in China nearly 3,000 years ago. At one time it was very expensive in Europe and was part of the valuable spice trade across Asia. Rhubarb guide lines say the leaves of the plant should not be eaten as they have a sour taste and contain harmful toxins.
Look for firm, crisp stalks something like celery. If snapped they should release sap easily. The stalks can be stored in the refrigerator for a couple of weeks and freeze well after cooking. Chop into 2-3cm chunks and stew over a low heat with very little water and sugar to taste. Apple or orange juice also works well as a sweetener if you don’t want to use too much sugar. The resulting stew is excellent eaten simply with custard or as a jam, as topping on breakfast cereal or in all sorts of desserts.