Jerusalem artichokes are one of those vegetables that divides opinion, although I suspect that more people dislike them than relish them. Even so, they have a kind of gourmet mystique that makes them seem ‘posh’ even though they are incredibly easy to grow and quite versatile in the kitchen.
They are basically sunflowers (Helianthus tuberosus) and their name derives (possibly) from Italian immigrants to North America who called them sunflowers (Girasol) which became Jerusalem. The ‘artichoke’ part of the name derives from the supposed resemblance in the flavour. They are distantly related to globe artichokes but they are a different genus and, of course, it is the immature flowerheads that are eaten there, not the tubers. Many perennial helianthus have creeping, tuberous rhizomes but none are as swollen as this, edible kind. In the USA they are also known as sunchokes, though this is a modern name, created in the mid 20th century. It is unusual as only one of a handful of commercial veg native to North America – it was an important food plants for Native Americans and was recorded as being cultivated in Cape Cod in 1605. The original range is probably from Newfoundland and Saskatchewan in the north to Georgia and Arkansas in the south. It was quickly sent to Europe as a foodstuff, received with varying degrees of enthusiasm, although, not being in the nightshade family like potatoes and tomatoes, it was not regarded with the same suspicion.
It is a hardy plant and the tubers can be left in the ground until harvested through autumn and winter, though the damage from slugs will then increase. The plants are tall, often exceeding 2m high, and they have small, yellow sunflowers though these are produced very late in autumn. The tubers should be planted in spring – I did mine yesterday – about 10 cm deep and 30cm apart. Protect the young shoots from slugs – and also rabbits and deer – and soon you will have a forest of stems. You can pinch out the growing tips when the plants are about 60cm high which will make them bushier and also shorter. Bear in mind that they are so tall and they may shade neighbouring crops. In late autumn, when the foliage goes yellow, cut the stems down to 10cm, so you know where they are, and harvest as needed. Harvesting needs to be thorough so you do not leave tubers in the soil that will sprout the following year. Each plant can produce as much as 2kg of tubers.
You can keep a few of the tubers to replant the following year – they are not prone to disease like potatoes and you can plant any that you find for eating in the supermarket. The most popular variety is ‘Fuseau’ which is supposed to be less knobbly than most. I have grown ‘Dwarf Sunray’ which is shorter and flowers earlier than most so is a dual-purpose plant since the yellow flowers are good for cutting. New garden and new start so this year I have obtained ‘Sugarball” which is supposed to be sweeter than most, with heavy crops of small tubers – we shall see!
Nutritionally, Jerusalem artichokes are interesting because they contain no starch. Instead the ‘energy’ is stored as inulin. Because this is not assimilated like starch it is suitable for diabetics. In storage the inulin changes to fructose, giving the sweet taste. Although the inulin is not digested in the gut, it is digested by bacteria in the gut which results, all too often, in flatulence. It is said that if you eat them regularly the symptoms are not as bad but it takes a leap of faith. I remember vividly the first time I ate them and also when I served them at a dinner party – don’t serve them in winter because you will want to open the windows! John Gerrard in his Herbal (1621), quotes from John Goodyer: ‘which way soever they be dressed and eaten, they stir and cause a filthy loathsome stinking wind within the body, thereby causing the belly to be pained and tormented, and are a meat more fit for swine than men.’
It is a shame that I can’t write about them without mentioning this unfortunate side of them because they do taste good, with a nutty flavour. They contain no fat and some protein. They can be cooked in many ways and even eaten raw. They go mushy quickly when boiled and are nicest fried or roasted. They are fiddly to peel and, if peeled raw, need to be put in acidulated water, before cooking, to prevent browning.
But here is a vegetable that is nutritionally useful, high in potassium and iron, that is hardy and easy to grow and does not need to be bought every year. Time will tell if I regret the decision to plant it again.