Common name: Jerusalem Artichoke

Native to North America, this perennial herb is closely related to the Sunflower (Helianthus annuus) and is cultivated for its tubers, which are cooked and eaten as a vegetable.

Clumps of tall, slender green stems sprout from the underground tubers. In highland tropical areas, these reach 1 to 1.5 m (3 to 5 ft) tall, about half the height they usually reach in subtropical and temperate regions. Dark green, ovate leaves 13 to 25 cm (5 to 10 in) long are set along the stems on long leaf-stalks. These are finely toothed along the margins and have a coarse, sandpaper feel. All parts of the stems and leaves are covered in fine hairs.

The flowers are bright yellow with a typical sunflower shape. However, they are much smaller and are on long stalks that emerge above the foliage. They bloom about three to four months after the tubers sprout.

The mature tubers are roundish with a distinctive, knobbly appearance, resembling a cross between a potato and a ginger root. They come in red-, purple-, or white-skinned varieties and range from 3 to 5 cm (1.2 to 2 in) in diameter.

Edible uses

Cooked vegetable - The tubers are thin-skinned, so they can be cooked with the skin on, much like the common potato, either whole or cut into pieces, then steamed, boiled, or baked. They are similar to the common potato but have a sweeter, nuttier taste and a crisper texture. When stored briefly, the inulin in the tubers converts to fructose, and they develop a much sweeter taste.

Pickled vegetable - They are also commonly pickled.

Natural gelling agent - The pulp is rich in the carbohydrate 'Inulin', which the food processing industry uses as a gelling agent, mainly for improving mouthfeel and creaminess in low-fat dairy products, such as low-fat yoghurt. It also gives these products a glossy appearance.

Flour - Some are processed into a slurry and then dried into a gluten-free flour with a mildly sweet, malt-like flavour. The flour has properties that promote the growth of beneficial bacteria in the human gut, which has led to its use in dietary supplements.

Natural sweetener - Some are also converted into a low-calorie syrup sweetener, closely similar to maple syrup.

Material uses

Livestock feed - Any excess tubers are fed to pigs. They have a reported crude protein content of around 7% of their dry weight.

Livestock forage - Pigs are also left to forage and unearth tubers missed during harvest.

Plant-based alcohol - Fuel-grade alcohol, ethanol, and butanol have been successfully produced from the tubers, though it does not appear this has been commercially exploited yet.

Cut-flower - The showy flowers resemble sunflowers but are much smaller. They are cut with their long stems for floral arrangements and have an average vase life of 7 to 10 days.

Health uses

The fructose that develops in the tubers is a suitable energy source for people with diabetes, as it is low in digestible calories. Cooked tubers also have beneficial bacteria-promoting properties.

Cooked tubers are also a good source of the following:
Potassium
Phosphorus
Vitamin B1 (Thiamine)
Iron

Climate

Although naturally adapted to warm-temperate climates, Jerusalem artichoke grows well and is productive in sub-humid to moderately humid subtropical and tropical highland climates, generally areas with annual lows of 9 to 17°C, annual highs of 15 to 28°C and yearly rainfall of 700 to 1900 mm.

Growing

New plants are usually started from tubers saved from the previous harvest and stored under cool, dark conditions, similar to requirements for other tuber crops. They are sown whole or in pieces when the air humidity builds, just before the rainy season.

Performs best on well-manured, loose, free-draining loam to sandy loam soils of a slightly acid to slightly alkaline nature, generally with a pH of 5.0 to 7.5, and on sites with full to partial sun exposure. Large or oversized containers with ample drainage are also suitable and produce good crops of tubers. It is intolerant of slow-draining, permanently wet or saturated soil conditions.

The tubers should be ready for harvest about three to four months after sowing, or about four to six weeks after the plant starts to flower. Tubers left in the ground and not foraged on by livestock will sprout to form new clumps of plants in the next growing season. Uncooked tubers have a relatively short shelf life, lasting about two weeks in the refrigerator.

Problem features

In at least one reference publication, it is listed as an invasive species, a weed classification reserved for the most serious weeds and is recorded as a weed of agriculture in Australia. Its weediness can be attributed to unharvested or missed tubers that re-sprout, forming new clumps of plants that can be difficult to control or eradicate.

Books

• Gohl, B. 1981, Tropical Feeds : feed information summaries and nutritive values (Revised edition), Food and Agriculture Organization of the United Nations (FAO), Rome

• Hanson, B. 2007, Buried treasures : tasty tubers of the world : how to grown and enjoy root vegetables, tubers, rhizomes, and corms, Brooklyn Botanic Garden, Brooklyn, New York

• Herklots, G. A. C. 1972, Vegetables in south-east Asia, Allen and Unwin, London

• Holttum, R. E. & Enoch, I. C. 2010, Gardening in the tropics : the definitive guide for gardeners, Marshall Cavendish Editions, Singapore

• Hunter, N. T & Mitchell, H. 1994, The art of floral design, Delmar Publishers, Albany, New York

• Imeson, A. 2010, Food stabilisers, thickeners and gelling agents, Wiley-Blackwell Publishing, Chichester, United Kingdom

• Morgan, D. & Achilleos, A. 2012, Roots : the definitive compendium with more than 225 recipes, Chronicle Books, San Francisco

• Norrington, L. & Campbell, C. 2001, Tropical food gardens : a guide to growing fruit, herbs and vegetables in tropical and sub-tropical climates, Bloomings Books, Hawthorn, Victoria

• Randall, R. P. 2002, A global compendium of weeds, R.G. and F.J. Richardson Press, Melbourne

• Randall, R. P. 2007, The introduced flora of Australia and its weed status, Cooperative Research Centre for Australian Weed Management, Glen Osmond, South Australia

• Tindall, H. D 1983, Vegetables in the Tropics, Macmillan Press, London

• Tindall, H. D. & Rice, L. W. 1990, Fruit and vegetable production in warm climates, International ed., Macmillan, London

• Toensmeier, E. 2007, Perennial Vegetables : From Artichokes to Zuiki Taro, A Gardener's Guide to Over 100 Delicious and Easy to Grow Edibles, White River Junction, Chelsea Green Publishing, Vermont

• Winters, H. F & Miskimen, G. W. 1967, Vegetable gardening in the Caribbean area, U.S. Dept of Agriculture, Washington D.C.