Stiff Goldenrod is an erect native perennial, the unbranched stem, which can be from 1 to 5+ feet high, is downy and frequently with a reddish color with age.
The leaves are grayish-green, stiff at maturity, oval, hairy, with the lower basal ones long-stalked with a shallow groove facing upward; the upper alternate leaves stalkless to extremely short stalks; margins may be slightly serrate. Leaves within the floral array become bracts. Basal leaves frequently persist through the winter.
The floral array is a grouping of branched clusters, large for the size of the plant, corymbiform in shape, that is - somewhat flat-topped - and the whole thing up to 10 inches wide. Stalks of the cluster and the individual flowers are hairy.
Flowers: Each small composite flower has 6 to 13 fertile (pistillate) yellow ray florets and a central disc up to 1/3 inch wide of 14 to 36 bisexual florets with yellow corolla tubes that have 5 lobes at the tip that are erect to spreading when open. The rays are very short - 1.4–5.4 × 1.2–1.9 mm in size. The disc florets have 5 stamens with yellow anthers. The stamens tightly surround the single style which is branched with a triangular appendage on the tip of each branch and greatly exserted from the corolla when the floret opens. The phyllaries (bracts) surrounding the outside of the flower head are in 3 to 4 series, oblong, of unequal length, appressed, have a green midrib with 3 to 5 pronounced nerves and rounded tips. The stalk of the flower has fine hair.
Seeds are ribbed dry cypselae, 0.8–1.7 mm long, obconic in shape (inverted cone) with a fluffy pappus for distribution by wind. Seeds of Solidago usually require 60 days of cold stratification and light for germination.
Varieties: There are 3 accepted subspecies of the species - details at bottom of page.
Habitat: Stiff Goldenrod grows well in dry sandy places and prairies that have full to partial sun with dry to moderate moisture. Too much water and rich soil is detrimental. It is fairy drought tolerant. The root system is a fibrous branching woody caudex. It grows easily from stratified seeds to produce plants the same season. It also self-seeds. If you have to move the plant, you can take offshoots from the root system.
Names: The common name and the species name, rigida, refer to the stiffness of the leaves. The genus name Solidago, is from the Latin solidare, as the plants of this genus were known to "make whole". (see bottom of page). The author name for the plant classification - 'L.' refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy.
Botanists have recently reclassified many members of the Aster family. Some, beginning with G. L. Nesom, have placed Stiff Goldenrod into the genus Oligoneuron from Solidago. The Oligoneurons have unbranched hairy stems and flat-topped clusters of bright yellow flower heads. However some major authorities such as Flora of North America (Ref. #W7) have raised objections to the reclassification and believe the species should be in Solidago Linnaeus sect. Ptarmicoidei, which consists of six species that have, among their traits, flat-topped arrays and persistent basal leaves. The issue is not settled. Minnesota authorities which usually follow the Flora, have also left it in Solidago.
Comparisons: Regardless of the scientific debate, you are unlikely to confuse this species with another in our area. The tall unbranched stem with the flat-topped clusters of goldenrod type flowers is distinctive.
Above: The flower heads shown here just opening are from late August, full heads from September. The floral array is a grouping of branched clusters, corymbiform in shape, at the stem-top.
Below: 1st & 2nd photos - The phyllaries are of unequal length with a darker green mid-rid and 3 to 5 prominent nerves. Stalks hairy. 3rd photo - The stiff upper leaves do not have stalks, but touch the downy stem.
Below: 1st photo - The lower leaves have long stalks and an adaxial groove. 2nd photo - The basal leaves are on long stalks and also have the prominent groove on upper side (adaxial) of the stalks.
Below: 1st photo - A detail of the disc florets with just 3 opening. Note the triangular shaped spreading lobes of the corollas on the open florets. 2nd photo - The fibrous root system of Showy Goldenrod which can produce offshoots from the caudex.
Below - Seeds: Seed heads of Stiff Goldenrod are very picturesque in the brown fall landscape. The seeds (2nd photo) are obconic shape ribbed cypselae with a fluffy white pappus attached.
Notes: Eloise Butler first recorded introducing Stiff Goldenrod to the Garden on August 23, 1910 with plants obtained from the area of Minnehaha Park (Minneapolis). Three more were transplanted from Glenwood Park (which surrounds the Garden) on Oct. 28, 1912 and Oct. 17, 1917. Other planting years were 1921, '22, '23, '24, '25, '26, '27 and '28. Stiff Goldenrod was listed on Martha Crone's 1951 inventory of plants in the Garden at that time and on each subsequent Garden census. Cary George noted planting it in 1995. The plant is native to Minnesota and widely distributed - reported in all but 14 widely scattered counties. It is present in the United States from the Rocky Mountains eastward. There are 18 species of Solidago known in the wild in Minnesota.
Subspecies: There are three accepted subspecies of Solidago rigidum: subsp. glabrata; subsp. rigida; and subsp. humilis. The latter two are found in Minnesota; however, the DNR does not break down the county data by subspecies. The differences between the subspecies are in details of the phyllaries of the flowerheads and the type of hair on the leaves and stem. In subsp. rigida, the inner phyllaries are oblong and rounded with sparser stiff bristly hair and the hairs on the stems and leaves are fewer than 50 per sq. mm. In subsp. humilis the inner phyllaries are often linear, heavy on the bristles and stems and leaves have more than 50 per sq. mm. If interested in more details consult Ref. #W7 for full details.
Medicinal Lore: The genus Solidago has several species, including rigidum, 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 S. rigidum, she reports that for stoppage of urine, the root was steeped in 1/2 pint of water and the dosage was to swallow occasionally. The same decoction was used for an enema. Mrs. Grieve (Ref. #7) reports on European use of the various species, and S. rigidum specifically, using the leaves and blossoms to treat hemorrhage.
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"