Description: This native perennial plant is up to 9'
tall and largely unbranched, except for an occasional side stem near the apex
bearing an inflorescence. The central stem is dull red or green, and covered
with
stiff white hairs.
The broadly lanceolate leaves are up to 10" long and 5" across, narrowing
rather abruptly into winged petioles about ½-2½" long. There is
coarse serration along the margins, and dense pubescence on the underside of
the leaves. This variety of Jerusalem Artichoke is distinguished by the more
conspicuous nature of this pubescence and its opposite leaves (except the
uppermost), while Helianthus tuberosus tuberosus has alternate leaves
from the middle part of the plant and upward. Near the apex are several
composite flowers on short stalks. Each daisy-like composite flower is yellow
and about 2½-4" across. The numerous disk florets are surrounded by
10-20 ray florets. There is little or no floral scent. The blooming period
occurs from late summer to fall, and lasts about 1½ months. The achenes
are grey or brown with longitudinal ridges, slightly downy, and up to 1/3"
long. The root system is tuberous or fibrous, and produces long rhizomes. There
is a tendency to form colonies by means of vegetative reproduction,
particularly in disturbed areas.
Cultivation: The preference is full or partial sun,
and moist conditions. The leaves will wilt conspicuously during drought, but
this plant recovers readily after significant rainfall. Growth is best when the
soil is fertile and loamy, where it may become aggressive. Disease usually
doesn't bother this plant until the fall, when powdery mildew on the leaves may
become troublesome. While in bloom, it may topple over during a wind
storm.
Range & Habitat:
Jerusalem Artichoke occurs throughout most of Illinois, except a few counties
in southern and NW Illinois (see
Distribution
Map). It is a fairly common plant, with both native populations and escapes
from cultivation. Habitats include moist to mesic black soil prairies, moist
meadows near rivers, woodland borders, thickets, borders of lakes, areas along
roadsides and railroads, and miscellaneous waste areas. This plant is usually
more common in disturbed areas in many of these habitats.
Faunal Associations: Bees are the most important
pollinators, although the flowers are also visited by bee flies, wasps,
beetles, and butterflies. Among the bees, are such visitors as bumblebees,
Miner bees, Halictine bees, and Panurgine bees. The flowers are usually
cross-pollinated by these insects, and rarely become self-pollinated. The
caterpillars of the butterflies Chlosyne nycteis (Silvery Checkerspot)
and Chlosyne gorgone (Gorgone Checkerspot) eat the foliage. Similarly,
the caterpillars of many moths and other insects feed on various parts of
Jerusalem Artichoke, including Pyrrharctia isabella (Isabella Tiger
Moth), Papaipoma rigida (Sunflower Borer Moth), Papaipoma rigida
(Rigid Sunflower Borer Moth), and Stibadium spumosum (Frothy Moth).
Other kinds of insects that feed on this plant include Publilia concava
(Treehopper sp., semi-shaded situations), Melanoplus angustipennis
(Spur-Throated Grasshopper sp.), and various beetles. The large nutritious
seeds are avidly consumed by various upland gamebirds, songbirds, and small
mammals (see Wildlife
Table). Large herbivores, such as livestock and deer, may eat the leaves
and flowers. Occasionally, the stems are used by muskrats and beavers for their
dens or dams.
Photographic Location:
The photographs were taken along the rocky slope of a drainage ditch at the
Windsor Road Prairie in Champaign, Illinois.
Comments: A better name for this sunflower would be
'Indian Potato' because the native people of North America cultivated and ate
the edible tubers, which are produced in substantial quantities. These tubers
have fewer calories per gram than the familiar 'Irish Potato' (a South American
plant), and are better for diabetics because the carbohydrates and sugars are
more easily assimilated by the body without insulin. This sunflower can be
reliably distinguished from other sunflowers by the winged petioles, which are
often ½" or longer on the larger leaves. With the exception of
Helianthus annuus (Annual Sunflower), the leaves of Jerusalem Artichoke
are wider than other prairie sunflowers in Illinois. It also has stems that are
covered with bristly white hairs, unlike Helianthus grosseserratus (Sawtooth
Sunflower), which has smooth stems.