This perennial wildflower is 2½-6' tall and usually unbranched, except
where the inflorescence occurs. The central stem is light green to
purplish green, sharply angled and sometimes narrowly winged, and
hairless or nearly so; sparse short pubescence may be present above.
Alternate leaves occur along the entire length of the stem, becoming
smaller as they ascend upward. The basal and lower cauline leaves are
4-12" long and 1½-4" across; they are more or less obovate in shape and
serrated along their margins, tapering to long winged petioles. The
middle to upper cauline leaves are 2-4" long and ½-1" across; they are
elliptic to oblanceolate in shape and slightly serrated to smooth along
their margins. The middle to upper cauline leaves are either sessile or
they have short winged petioles. The upper surface of the leaves is
medium green and either hairless or covered with stiff minute hairs;
the lower surface of the leaves is hairless and smooth. Sometimes the
basal and lower cauline leaves become greenish yellow or wither away by
the time the inflorescence appears.
The central stem terminates in an
open panicle of flowerheads up to 1½' long and 2' across. On a
robust plant, this panicle has long primary branches that are ascending
to widely spreading; they are often recurved. Each primary branch of
the panicle is divided into short secondary and tertiary branches that
terminate in clusters of erect flowerheads (see photo of Flowering
The branches of the panicle
are hairless or sparsely short pubescent. Leafy bracts up to 1" long
and ½" across occur along these branches. Individual flowerheads are
about 1/8" across, consisting of 5-12 ray florets that surround
5-15 disk florets. Individual ray florets have yellow corollas that
are petal-like; they are pistillate and fertile. Individual disk
florets have yellow corollas that are narrowly tubular with 5 spreading
lobes; they are perfect and fertile. At the base of each flowerhead,
there are appressed phyllaries (floral bractlets) in several series
that are green and narrowly oblong in shape. The blooming period occurs
from late summer into the fall for about 1-1½ months. The florets are
replaced by small bullet-shaped achenes with tufts of hair. The
achenes are sparsely hairy; they are distributed by the wind. The root
system is fibrous and rhizomatous; sometimes a small caudex will form
on an older plant. Clonal offsets often develop from the rhizomes.
The preference is partial sun to light shade, wet to consistently moist
soil that consists of loam or sandy loam with organic matter. Some
plants may lean over to the side if they lack adequate support from
adjacent vegetation. A low area that is protected from the wind is
The native Swamp Goldenrod is
occasional in sandy areas
of northeast and central Illinois, while in the rest of the state it is
uncommon or absent (see Distribution
). Habitats include typical swamps, sandy swamps,
shrubby fens, shaded seeps, sandy pannes and interdunal wetlands near
Lake Michigan, and bogs. Swamp Goldenrod prefers shaded wetlands where
the soil is either sandy or non-sandy; it is usually found in higher
quality natural areas.
The nectar and
pollen of the flowerheads attract long-tongued bees, short-tongued
bees, wasps, flies, beetles, and other insects. The following bees are
specialist pollinators of Solidago
and Colletes simulans
. Some of these bees
also visit Aster spp.
(Asters). Other insects feed on the foliage,
flowers, and other parts of goldenrods. These species include the
caterpillars of Schinia
(Goldenrod Flower Moth),
(Goldenrod Leaf-Mining Moth), and other
moths (see the Moth Table
more complete listing of species).
Other insect feeders include Acuticauda
aphids, the leafhoppers Empoasca
(Chrysanthemum Lace Bug), Lopidea media
(Goldenrod Plant Bug) and other plant bugs, Homaemus aeneifrons
and other stink bugs, Calligrapha californica
and other leaf
(Goldenrod Gall Fly) and other gall flies (see
the Insect Table
more complete listing of species).
Vertebrate animals are more sparing in their use of goldenrods as a
food source. Both beavers and muskrats eat the stems of wetland
goldenrods to a limited extent, while deer occasionally browse on the
foliage. The Ruffed Grouse occasionally eats the foliage, while the
Swamp Sparrow and other granivorous songbirds occasionally eat
the seeds. When colonies of plants are formed, Swamp Goldenrod provides
significant cover for various kinds of wildlife in wetlands.
A sandy swamp at the Indiana Dunes
State Park in NW Indiana.
This tall goldenrod has a rather messy inflorescence that sends
flowering branches in all directions. Swamp Goldenrod is relatively
easy to distinguish from other Solidago
(Goldenrods): 1) It usually occurs in
shaded wetlands, rather than areas that are more sunny or dry, 2)
it often has large basal and lower cauline leaves up to 12" long and 4"
across, 3) its central stem is sharply angular and sometimes winged,
and 4) on robust plants, it has an open inflorescence with flowering
branches that are widely spreading or recurved.