Downy Ragged Goldenrod* (Solidago petiolaris**) of the Aster, Sunflower, or Composite (Asteraceae) family has stiff lanceolate leaves on unbranched stems that are topped by an unusually large array of golden-yellow flower heads. The genus name is based on the Latin solidus, meaning “whole,” in reference to purported health benefits of some species. The specific epithet is from the Latin for “with petiole.” In the U.S., the species occurs primarily from southern Nebraska and Texas, east to the Carolinas and northern Florida. In Arkansas, it occurs statewide except for portions of the Mississippi Alluvial Plain and Crowley’s Ridge. Preferred habitats include more or less sunny, mesic to dry, sandy to rocky areas, such as open woodlands, glades, and blufftops. It is also known as Woodland Goldenrod.
This herbaceous perennial develops a central rootstock of weakly connected segments with numerous fibrous roots. Each knobby segment bears one to several stems. Buds for the next year’s stems develop at the base of the current year’s stems. Dead stems persist into the new growth-year. Erect, fleshy springtime stems tend to be pubescent and reddish, while mature stems become reddish brown to brown below as they stiffen. Stem growth above in the inflorescence tends to be bright green before also becoming reddish to brown.
Stems, with slight longitudinal ridges, grow to unequal heights, often reaching 4+ feet tall and, at base, 3/16 inch in diameter. They are unbranched unless the growing tip has been damaged. Lower portion of stems typically loses leaves by mid-growth-year, becoming smooth except for projecting petiole bases. Depending on the site, they may be erect, ascending or sprawled.
Plants have alternate, simple stem leaves, narrowly elliptic, spreading to ascending, and stiff, at midstem to 4 inches long and ½ inch wide, gradually decreasing to as little as ⅛ inch long in the terminal inflorescence. They are sessile to short-petiolate, with margins entire (smooth) to shallowly serrate distally, the teeth mucronate. Upper leaf surface is green with a satin sheen, the lower surface with a dull sheen. Venation is pinnate with a single strong midvein and secondary veins that curve forward to parallel the margins. Mature leaves feel slightly rough from microscopic hispid pubescence, with hairs more prominent on the main veins beneath. Margins are ciliate with the hairs angled toward the apex. As soil dries during summer, leaf-drop proceeds up-stem.
Composite flower heads, with ray and disk florets, bloom in September and October. The axillary inflorescence, along the upper portion of the stem, consists of individual flower heads and tightly branching clusters of 3 to 7 flower heads, forming columnar or spikelike panicles. An inflorescence may be 4 to 10 inches long with up to 150+ heads, the flowering proceeding from apex to base. Individual heads or clusters are subtended by a small leaflike bract. While pedicels of single flower heads are consistently short, peduncles of clusters may be a bit longer (to ½+ inch). When plants are erect, flower heads are arranged equally around the stem; when sprawled, heads twist toward sunlight so that the inflorescence is secund (heads all on upper side). Pedicels and peduncles bear closely spaced linear-oblong bracts that transition to the linear-lanceolate phyllaries of the involucre (to ¼ inch long). Heads are about ¼ inch long and ⅛+ inch wide. Pedicels, peduncles, bracts, and phyllaries are light green with short hooked pubescence, that of the phyllaries being glandular.
The golden yellow flower heads comprise 5-10 pistillate (with pistils only) ray florets that surround 8-18 perfect (with pistils and stamens) disk florets subtended by an elongate cuplike involucre. The involucral bracts (termed phyllaries in the composites) are disposed in 3-4 series, with spreading to sharply recurved, triangular tips that give the heads a bristly appearance. Inner and outer surface of phyllaries bear minute glandular pubescence which may cause them to feel viscid. Heads bloom centripetally, from the ray florets inward to the center. Ray florets have a single linear to oblong ligule (the exposed portion of the corolla), ¼+ inch long, that has several longitudinal pleats, a rounded apex and tapered base.
Disk florets have tubular corollas, 5 stamens (filaments + anthers) and 1 pistil (ovary + style + stigma). The corollas, about 3/16 inch long, are topped with five narrow, erect, triangular lobes. Anthers of the free staminal filaments are fused together into a ring surrounding the style. As the style elongates through the anther ring, it carries the pollen above the corolla, where it is available to be dispersed by pollinators. With pollen released, anthers wither and the exserted style narrowly bifurcates to expose linear stigmatic surfaces for pollen capture. Corollas of disk florets are surrounded by a pappus of straight hairs, attached to the summit of the inferior ovary.
Fertilized ray and disk florets produce flattened elongate achenes (referred to as cypselae in Aster family) topped by pappus. The ⅛ inch long achenes are longitudinally ribbed. Dry pappus radiates from the apex of the achene where it provides lift for wind dispersal.
Downy Ragged Goldenrod, with its large and decorative, late-summer and fall inflorescence, is an excellent choice for a wildflower garden. As with other goldenrods, its flowers provide nectar and pollen for a wide variety of insects, and seeds are consumed by small song birds. The long graceful stems can be somewhat “disorganized” so that staking may be needed. Plants do not spread by rhizomes. When soil dries, this species seems to be more prone to leaf drop.
Downy Ragged Goldenrod is one of some 30 or more species, subspecies, and varieties in the Solidago genus recognized in Arkansas. Of all these species, it most closely resembles Buckley’s Goldenrod (Solidago buckleyi) which has a similar inflorescence and spreading to recurved phyllaries. Buckley’s Goldenrod has fewer and significantly larger and thinner leaves that consistently have prominent marginal teeth.
*“Downy” may be a reference to early pubescence of stems and leaves which is mostly lost with plant maturity. “Ragged” may be based on the plant’s overall appearance at bloom-time: its long unbranched stems of varying lengths; its firmly positioned, often sprawling and twisty stems; and leaves that drop as available moisture declines.
** Leaf and phyllary shape and pubescence are variable across its range. Some authorities recognize varieties that are not addressed here. Arkansas plants are in need of further study.
Article and photographs by ANPS member Sid Vogelpohl