Description: This native perennial plant branches
occasionally and is 2½–4' tall. The central stem and side stems
have spreading white hairs, particularly in the upper part of the plant. The
alternate leaves are up to 5"
long and 2" across. They have a soft texture and are
covered with fine white hairs. Their margins are smooth, but ciliate. Some of
the lower leaves may be deeply three-lobed, otherwise the leaves are unlobed
and lanceolate to broadly lanceolate. The base of the leaves are sessile, clasp
the stem, or have short winged petioles. The daisy-like compound flowers occur
individually at the ends of major stems. They are about
2½–3½" across, with 6-18 yellow ray florets surrounding a
rounded central cone of numerous tiny disk florets. This central cone is
reddish brown and often shiny in bright light. The compound flowers have little
or no floral scent, although the cones or leaves may produce an anise fragrance
if they are torn apart. The blooming period occurs from mid- to late summer and
lasts about a month or slightly longer. The dark slender achenes are without
tufts of hair. The root system is shallow and fibrous, occasionally producing
rhizomes.
Cultivation: The
preference is full or partial sun and moist to mesic conditions (moist if
located in a sunny spot). Tolerance of shade is better than most plants that
occur in prairies, while tolerance of dry, sunny locations is poor. The soil
should consist of loam with abundant organic matter, although a little gravel
or sand is not harmful. This plant seems to resist powdery mildew better than
other Rudbeckia spp., such as Rudbeckia hirta (Black-Eyed
Susan).
Range & Habitat: Sweet
Coneflower occurs occasionally in the majority of counties in Illinois; it is
more common in northern and central Illinois than southern Illinois (see
Distribution
Map). Habitats include moist black soil prairies, sand prairies, savannas,
thickets, openings in floodplain forests, woodland borders, partially shaded
gravelly seeps, riverbanks, and roadside ditches. This species is usually found
in higher quality habitats. It is sometimes cultivated in gardens.
Faunal Associations: Many kinds of insects visit the
flowers, including long-tongued bees, short-tongued bees, wasps, flies,
butterflies, beetles, and plant bugs. Most of these insects seek nectar, but
bees occasionally collect pollen for their larvae, while beetles often feed on
the pollen. A specialist visitor of the flowers is the short-tongued Panurgine
bee, Heterosarus rudbeckiae. Little information about this plant's
relationship to mammalian herbivores is available, although many of them
probably eat the foliage occasionally as it is not known to be toxic. The anise
scent of the foliage in some plants may provide a limited amount of
protection.
Photographic Location:
The photographs were taken along a path at Crystal Lake Park in Urbana,
Illinois.
Comments: Sweet Coneflower
is longer-lived than either Rudbeckia hirta (Black-Eyed Susan) or
Rudbeckia triloba (Brown-Eyed Susan). It can be distinguished from these
species by the soft fuzzy texture of the leaves and the shiny appearance of the
central cone in the flowerhead. It is taller than Black-Eyed Susan and has
larger flowers than Brown-Eyed Susan. At favorable locations, Sweet Coneflower
has attractive foliage and flowers, otherwise it will appear rather
dilapidated.