Showy Goldenrod is an erect native perennial forb with an unbranched stem that can be from 8 to 72+ inches high. Roots may send up multiple stems which are smooth and usually reddish but the branches within the floral array can have fine hair.
Leaves: The lance-shaped leaves are usually not hairy, and the upper stem leaves are much smaller. Depending on the variety, the margins may be entire to having a few coarse teeth to many fine teeth and the leaf may be stiff to not stiff. Leaves have a tapering base to the stem that appears like a short winged stalk. The very largest basal leaves may be more elliptic in shape. From the upper stem leaf axils fascicles of small leaves often appear. The underside of the leaf is paler in color with fine hair along the mid-rib.
The floral array is a dense branched panicle that is taller than it is broad, at the top of an unbranched stem. Flowering branches of the panicle are held erect, not drooping or bending like most goldenrods. Small green bracts are scattered along the stalks of the flower clusters and on the stalks of individual heads. On a large plant it is a magnificent sight.
Flowers: The individual flowers have two types of florets: There are 3 to 7 outer ray florets with yellow rays, not all open (extended) at the same time, giving an unequal spacing look. These are pistillate and fertile. These surround 6 to 16 bisexual and fertile disc florets have a tubular five lobed yellow corolla with out-flaring apex lobes; five stamens tightly surround a branching style which has small appendages at the tips and which is exserted from the corolla throat when the floret opens. The phyllaries of the outside of the flower head are in 3 to 4 series, unequal in size, yellowish with translucent margins and sometimes may be slightly sticky. They are linear, but short, overlapping and appressed to the head.
Seed is a dry cypsela, shaped like a thin inverted cone (1.6 to 2.5 mm long) with a fluffy white pappus at the thick end for wind distribution. Seeds of Solidago usually require 60 days of cold stratification and light for germination. They should be surface sown.
Varieties: There are four varieties of the species but only two (a third is in question) in North America. Details at bottom of the page.
Habitat: Showy Goldenrod grows from a rhizomatous and fibrous root system which develops woody caudices. It grows best in full sun with dry to moderate moisture and well-drained soils. The rhizomes allow the plant to spread vegetatively and the plant can develop good colonies, crowding out most other plants.
Names: The genus name Solidago, is from the Latin solidare, as the plants of this genus were known to "make whole". (see bottom of page for medicinal lore). The species name speciosa, means "showy". An older name for this species isSolidago rigidiuscula. The University of Minnesota Herbarium still uses this name. The author name for the plant classification - ‘Nutt.’ refers to Thomas Nuttall (1786-1859) English botanist who lived and worked in America from 1808 to 1841. On his many expeditions he collected many species that had been originally collected by Lewis and Clark but lost by them on their return journey.
Comparisons: Of all the goldenrods in our area, this is the most easily recognized by its unbranched stem with a panicle of ascending branches densely covered with flower heads.
Above: The large and magnificent floral array. Drawing courtesy Flora of North America.
Below: The flower has are outer group of ray florets surrounding the inner disc florets. Not all the ray florets have rays extended at the same time.
Below: 1st photo - The phyllaries of the outside of the flower head are in 3 to 4 series, unequal in size, yellowish with translucent margins and sometimes may be slightly sticky. They are linear, but short, overlapping and appressed to the head. 2nd photo - The smooth reddish stems and lance shaped upper stem leaves of Showy Goldenrod.
Below: The basal leaf clump in early spring.
Below: The basal leaf and an upper stem leaf of S. speciosa var. rigidiuscula. Note the fascicles of small leaves at the base of the upper leaf.
Below: Seeds have a long white fluffy pappus to catch the wind. Seeds are thin, shaped like an inverted cone.
Below: The underside of the leaf is paler in color with a little fine hair along the mid-rib. 2nd photo - The root is rhizomatous with woody caudices.
Below: The root is rhizomatous with woody caudices, allowing the plant to form large clumps.
Notes: Showy Goldenrod is not indigenous to the Garden area. On Sept. 3, 1914 Eloise reported planting var. angustata, obtained from Minnehaha Park. Martha Crone noted the species in bloom in 1938. Showy Goldenrod was listed on Martha Crone's 1951 Garden Census. It is native to Minnesota in a wide band of counties running from the SE to the NW, rarer in the SW the the NE. In the U.S. S. speciosa is found from the Rocky Mountains east to the coast excepting Alabama, Florida and Maine. In Canada it is known only in Ontario.
Varieties: There are 18 species of Solidago known in the wild in Minnesota. According to Flora of North America, there are two recognized varieties of S. speciosa within North America, with both of those varieties recognized as being native to Minnesota - var. speciosa and var. rigidiuscula. The latter once had the name var. angustata which is a name Eloise Butler used. The range of the two varieties in the U.S. overlaps Minnesota geographically. The MN DNR does not track survey data by variety however. Var. speciosa has dark green leaves with basal leaves usually present at flowering time, often coarsely toothed, with mid-stem leaves not crowded, not stiff or rough. Var. rigidiuscula has basal leaves mostly entire to having a few shallow teeth and sometimes not present at flowering time. The mid-stem leaves are often crowded, stiff and somewhat rough. A third variety, known as var. pallida, is found only in a small section of the western part of the range and has pale green leaves with whitish tones. It has not been established whether this type should be recognized as a separate variety of whether it is a local variation of the others.
Medicinal Lore: The genus Solidago has several species including, speciosa, whose leaves and tops and roots were used by natives for various disorders. Here in Minnesota, Frances Densmore (Ref.#5) reported that the Chippewa used various species of Goldenrod for treating fevers, colds, ulcers and boils. Specifically in regards to S. speciosa, a decoction from pulverized roots was drank to treat lung trouble. A similar decoction was taken for hemorrhage when bleeding from the mouth occurred; another root decoction helped women with difficult childbirth labor. Boiled stalk or root was used as a warm compress on sprains when swelling occurred. These same decoctions of root would be used as general tonics. Dried stalk or root, combined with bear grease formed an ointment. Mrs. Grieve (Ref. #7) reports on European use of various species.
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"