Description: This herbaceous perennial plant is 3-8' tall and largely unbranched, except where the flowers occur. The central stem is stout, round, light green to light red, and densely covered with short white hairs. The leaves occur alternately along the central stem, except for some of the lower leaves, which may occur oppositely from each other. These leaves are up to 12" long and 2" across. They are sessile against the stem, and narrowly lanceolate. Their upper and lower surfaces are light green and covered with fine white hairs. The margins of the leaves are smooth, or they may have widely spaced small teeth. Furthermore, the typical leaf folds upward from the central vein, and curls downward from the stem on account of its length.
From the axils of
the upper leaves, there are short flowering stalks. Each of these
stalks is more or less erect, bearing a single composite flower and
possibly 1 or 2 leaves. Each composite flower is about 2–3½" across.
There are 20-40 yellow ray florets, which surround numerous disk
florets. Behind each composite flower, there are green bracts that are
lanceolate or narrowly lanceolate; they are covered with fine white
hairs as well. The blooming period is late summer to fall and lasts
about 1 month. The achenes are linear-oblong with a pair of awns on
top. They are blown about by the wind, or distributed by animals. The
root system consists of fleshy, fibrous roots and rhizomes. Like other
perennial sunflowers, this plant can form vegetative colonies.
Cultivation:
The preference is full sun and mesic to dry conditions. The soil can
contain clay-loam, rocky material, or loess. This plant appears to have
few problems with pests or foliar disease. It can grow tall and spread
aggressively, and may flop over while in bloom if it is grown in moist
rich soil.
Range &
Habitat:
Maximilian's Sunflower is an uncommon plant that occurs in NE Illinois,
west central Illinois, and SW Illinois (see Distribution
Map). It is adventive from the west in most, if not all, of
these areas. It is possible, however, that Maximilian's Sunflower is
native to a few of the western counties in Illinois where it occurs in
high quality
natural habitats. Habitats include rocky upland prairies, loess hill
prairies, ledges of rocky cliffs, areas along railroads and roadsides,
and waste ground. This plant is more common in states that lie west of
the Mississippi River.
Faunal Associations:
The flowerheads of this species probably attract many of the same insects
as other sunflowers, including long-tongued bees, short-tongued bees,
butterflies and skippers, and beetles. These insects seek nectar or
pollen. Other insects feed destructively on the foliage and other parts of sunflowers. For example, the caterpillars
of the butterfly Chlosyne nycteis (Silvery
Checkerspot) feed on their foliage, while the caterpillars of several Papaipema
spp. (Borer Moths) bore through their stems (see the Insect
Table for additional species that feed on sunflowers). Among
vertebrate animals, the seeds of sunflowers are an attractive source of
food for various upland gamebirds and songbirds (see Bird Table).
The Franklin Ground Squirrel and Thirteen-lined Ground Squirrel also
eat the seeds of these plants, while the Plains Pocket Gopher feeds on
their roots. The
foliage of young plants may be eaten by rabbits and groundhogs, while
large plants are eaten by livestock.
Photographic
Location:
A city park in Champaign, Illinois, where a colony of plants occurred
along a small lake.
Comments:
Maximilian's Sunflower is named after an early botantical explorer of
North America. This plant has attractive foliage and flowers, and it is
easy to identify because of the unusual leaves. These narrow leaves are
longer (up to 12") than the leaves of other Helianthus spp.
in Illinois, and they have a distinctive light green or greyish green
appearance because of their fine white hairs. Two native species, Helianthus
grosseserratus (Sawtooth Sunflower) and Helianthus
giganteus (Giant Sunflower), also have narrow leaves, but
they are not covered with dense white hairs. Another species resembling
Maximilian's Sunflower is Helianthus salicifolius
(Willow Sunflower), which occurs in the southern Great Plains. The
Willow Sunflower has narrow leaves that are even longer than
Maximilian's Sunflower, but they are only ½" across or less. The Willow
sunflower is not known to occur in Illinois at the present time,
although a colony of 500 plants once existed in Cook County before it
was destroyed by commercial development. These plants were undoubtedly
adventive from the west. Sometimes the scientific name of Maximilian's
Sunflower is spelled Helianthus
maximilianii.