Jerusalem Artichoke (Helianthus tuberosus)
Daisy Family (Compositae)
Canada potato, earth-apple, girasole, sunflower artichoke, sunroot, tuberous sunflower.
Origin and Distribution:
Jerusalem artichoke is native to North America and may have originated in the Ohio and Mississippi River valleys. The first written account of the plant was a report issued in 1605 by Champlain, a European explorer, who observed Native Americans growing Jerusalem artichoke along with corn and beans in a Cape Cod garden. The species was introduced to Europe in 1612 where it gained popularity as both human and animal food. Its current range in North America extends from the East Coast to the Midwest, and from southern Canada to Georgia. Jerusalem artichoke occurs in all but a few northwestern counties in Ohio. This native plant inhabits riverbanks, roadsides, fencerows, and agronomic fields, preferring rich, moist soils.
It is nearly impossible to distinguish Jerusalem artichoke from annual sunflowers based on above-ground growth. Jerusalem artichoke has a coarse, 5- to 10-foot tall stem, large leaves with a rough upper surface, and bright yellow sunflower-like flowers. However, Jerusalem artichoke can be easily distinguished from annual sunflowers by its below-ground growth that includes fleshy tubers resembling thin, knotty potatoes. Reproduction of Jerusalem artichoke is by seeds, rhizomes (horizontal underground stems), and tubers.
The root system is fibrous with thin cord-like rhizomes (horizontal underground stems) that grow as long as 50 inches. Usually apparent at the tips of rhizomes are whitish to pinkish tubers that are irregular in size and shape and resemble a slender potato with knots.
Seedlings and Shoots:
The first leaves to emerge (cotyledons) have a united base in the shape of a short tube. Young leaves are elliptic, dull green, and covered with short stiff hairs.
Jerusalem artichoke stems grow as tall as 12 feet, and are stout, rough, hairy, ridged. Stems can become woody over time. Branches vary from none to many.
Leaves are opposite (2 leaves per node) on the lower part of the stem, and alternate (1 leaf per node) near the top of the stem. Leaves are 4 to 10 inches long and nearly heart-shaped with a broad oval base and pointed tip. The thick leaves have 3 distinct main veins, coarsely-toothed margins, and attach to the stem by way of a winged stalk (petiole). The upper leaf surface has coarse hairs while the lower surface has soft hairs.
Flower heads occur alone or in groups at the ends of main stems and axillary branches. Each flower head is 2 to 3 inches wide and made up of many small, yellow, tubular disk flowers in the center, surrounded by 10 to 20 yellow ray flowers (typically thought of as the petals).
Fruits and Seeds:
Seeds are smooth, wedge-shaped, and gray or brown with black mottling.
Common sunflower (Helianthus annuus) is an annual that shares many above-ground characteristics with Jerusalem artichoke but below ground, it lacks rhizomes and tubers. Black-eyed Susan (Rudbeckia spp.) is generally a much smaller and bushier plant, although its flowers are very similar in appearance to those of Jerusalem artichoke.
Jerusalem artichoke is sometimes cultivated for its edible tubers, but it can become an aggressive weed that is very difficult to control. Plants flower from August to October. Seeds are usually produced in low numbers, so tubers are the primary mechanism by which plants reproduce. Tubers are also the means by which plants survive winter, since the foliage dies back after frost. Tubers sprout in late spring and are capable of forming shoots even if buried 12 inches deep in soil. As many as 6 shoots may emerge from one tuber. New tuber formation begins just before flowering. A single Jerusalem artichoke plant can produce 200 tubers in one growing season, but typically plants produce around 75 tubers. Jerusalem artichoke is a competitive plant when growing with row crops, where just a few plants can significantly reduce yields. However, because it is highly nutritious, its presence may be desirable in pastures. Foliage is used to make silage and tubers are fed to livestock. Pigs are especially fond of the tubers, and commonly dig up and eat buried tubers, which helps control the plant's spread. Although tubers are the primary means of reproduction, they only survive a couple of years in soil. Therefore, preventing tuber formation by repeatedly applying control measures for 2 years will generally control Jerusalem artichoke. Application of selective herbicides at the pre-bloom stage generally results in good control.
Facts and Folklore:
The common name is probably a corruption of the Italian 'girasola' meaning 'turning to the sun' (as in many sunflower species, Jerusalem artichoke flowers follow the movement of the sun across the sky) and 'articiocco' meaning 'edible'.
Jerusalem artichoke was cultivated in North America about 400-500 years ago, and the Lewis and Clark expedition ate Jerusalem artichokes provided by Native Americans during their journey across the U.S.
The sugars from one acre of Jerusalem artichoke can produce 500 gallons of alcohol, which is about double the amount produced by either corn or sugarbeet.