JERUSALEM artichokes, those knobbly tubers at the greengrocers, have nothing to do with Jerusalem. They are, in fact, a type of sunflower, native to the North American plains. As a vegetable they have an appalling reputation - which cannot be denied - for provoking flatulence. However, they taste earthy, sweet and ambrosial, and are "a dainty for a queen" according to John Parkinson, the 17th-century botanist.

A line of Jerusalem artichokes planted now - each tuber six inches deep and 12 inches apart - will act as a temporary screen or a windbreak in the garden; the rather coarse, leafy plants will grow six or 10 feet tall before withering at first frost. They are not fussy about their site, and will grow in ground shunned by most vegetables, although the best crop will be obtained in a light, rich soil. Water during dry spells. Dig them up as you need them from late November on. They can become invasive, so be sure to clear all tubers from the ground when you are planting a different crop.