The late summer and the early fall brings out many colorful species of wildflowers. Many of these species are Goldenrods. Our most common local Goldenrod species is the Canada Goldenrod (Solidago canadensis).
Canada Goldenrod is a member of the Order Asterales, Family Asteraceae or Compositae, the Subfamily Asteroideae, the Supertribe Asterodae, and the Tribe Astereae.
The generic name, Solidago, comes from the Latin words, solidus and ago, which means “to make solid” or “to make whole”. It may refer to the healing properties of this genus. The specific epithet, canadensis, is New Latin for “of Canada”.
Other scientific synonyms for this species are Aster canadensis (L.) Kuntze, Doria canadensis (L.) Lunell, Solidago altissima L., S. hirsutissima Miller, and S. lunellii Rydberg. (Some references list S. altissima as a separate species or as a variety). Other common names for this species are Canadian Goldenrod, Common Goldenrod, Giant Goldenrod, Late Goldenrod, Meadow Goldenrod, Tall Goldenrod, and Tall Yellowweed.
DESCRIPTION OF THE CANADA GOLDENROD
Height: Its height is 1-8 feet.
Stem: Its stem is green or grayish, erect, and unbranched. It has sparse lines of white hairs near the top and is smooth near the bottom.
North American Beavers (Castor canadensis Kuhl) and Muskrats (Ondatra zibethicus L.) use these stems in building their dens.
Leaves: Its leaves are dense and alternate. Each leaf is short-stalked or sessile, about 2-6 inches long, about 1-1½ inch wide, rough above, and slightly hairy below. They are narrowly lanceolate, narrowly oval, elliptic, or broadly linear and are tapered at both ends. These leaves are larger near the center but become smaller near the apex. Its margin is both remotely and sharply toothed near the tip. It is 3-veined with their 3 veins being parallel to each other. The lower leaves fall during flowering season.
White-tailed Deer (Odocoileus virginianus Zimmermann) and Eastern Cottontail Rabbits (Sylvilagis floridanus J.A. Allen) eat the leaves. However, this plant is not a preferred food.
Flowers: Its flowers are arranged in 1-sided, terminal, pyramidal or plume-like, outwardly branching, racemous clusters. These clusters are about 2-16 inches high. The individual flower heads are closely clustered together. Each flower head is almost ¼ inch wide and almost 1/8 inch long. Each flower has 6-20 small yellow ray flowers and 2-8 small yellow disk flowers. These flowers are fragrant. The flowers usually don’t arrive until the 2nd year. Flowering season is July to November. A single flower may stay in bloom for 3 weeks.
These flowers are insect-pollinated. When pollinating, the insects walk over several flower heads to insure cross-pollination. Unlike the Ragweed (Genus Ambrosia), its pollen does not cause hay fever. Goldenrod pollen is too heavy, too wet, and too sticky to be airborne.
Fruit: Its fruit is a 1-seeded, hairy achene. The achene is longitudinally ribbed and is tipped with small tufts of numerous white hairs. This seed is dispersed by the wind.
American Goldfinches (Spinus tristis L.) and Swamp Sparrows (Melospiza georgiana Latham) eat these seeds.
Roots: Its root system is shallow and fibrous. It also has a deep taproot that may extend as deep as 11 feet. These roots may have mycorrhizal fungi.
This plant has reddish, 2-5 inch long, creeping rhizomes that grow in the fall and later form dense clonal colonies. These colonies may extend up to 8-30 feet in diameter. The young shoots may stay connected to the rhizome for up to 4 years. Each shoot can produce 2-6 more rhizomes that radiate outward and each rhizome can send up 1 more shoot.
These clonal colonies can be very dense and will keep out other plant species. All members of this colony are of the same height. Some colonies are over 100 years old. The older, central plants die and leave a large ring of plants that gets larger over time.
Habitat: Its habitats consist of clearings, fields, meadows, pastures, open woods, thickets, roadsides, fencerows, disturbed areas, and prairies. Canada Goldenrods are shade intolerant and cannot thrive within the deep woods.
Range: Its range covers the eastern U.S., excluding Florida, as far west as the Rocky Mountains, and southeastern Canada.
Canada Goldenrods are highly susceptible to spherical Goldenrod Galls upon their stems. The Goldenrod Gall Flies (Eurosta solidaginis Fitch) lay their eggs upon the stem. The egg hatches in about 10 days and the larvae secretes a chemical that causes the stem to swell. The larva bores a hole into the swelling and overwinters inside. Their bodies produce an antifreeze chemical to protect them from freezing temperatures. During this time, Chickadees (Genus Poecile) and Downy Woodpeckers (Dryobates pubescens L.) may peck out the larva for food. The fly emerges as an adult in the spring. The adults live about 2 weeks, mate, and die.
Canada Goldenrod has a few medicinal uses. The Native Americans and the early European colonists used this plant as medicine. A root and flower infusion was used for side pains and as an emetic for gall. A shoot infusion was used as a febrifuge. The flowers were chewed to relieve sore throats. A flower or root poultice was used for treating boils, burns, and ulcers. The leaf extracts were used as a diuretic and as an antispasmodic.
Canada Goldenrod has some edible uses, too. The Native Americans and the early European settlers used this plant as food. The seeds may be eaten as food. The roots can be steeped and eaten. The fresh or dried flowers were made into tea.
The fresh flowers were used as a yellow dye. This dye was most effective upon wool and silk.
Canada Goldenrod had other uses as well. It was used as a good luck charm for gambling, a play whip for children, and was smoked with tobacco.
The galls, also called “rheumaty buds”, were used by superstitious New Englanders. They believed that carrying these galls around with the larvae inside would ward off rheumatism.
Canada Goldenrod is sometimes planted as an ornamental plant. Unfortunately, it has become an invasive plant in Europe, China, and Japan.
It was introduced into China in 1935 and has reached pandemic levels in the eastern 1/3 of the mainland. It has crowded out native species and has reduced crop production. The Chinese government has started a massive program to eradicate this plant.
This plant is also a problem in Japan. It has now taken over rice fields abandoned after its 2011 nuclear power plant disaster.
Canada Goldenrod can even become a nuisance in the United States. It can crowd out other plants and become a monoculture.
The roots exude a phytotoxic substance that can inhibit other plant species, such as Maples (Genus Acer). Maple sugar farms would not want this plant.
WILDFLOWERS OF WISCONSIN
By Merel R. Black and Emmet J. Judziewicz
WILDFLOWERS IN THE FIELD AND FOREST
By Steven Clemants and Carol Gracie
WILDFLOWERS AND WEEDS
By Booth Courtenay and James H. Zimmermann
COMMON FLOWERING PLANTS OF THE NORTHEAST
By Donald D. Cox
WILDFLOWERS OF THE EAST
By Mabel Crittenden and Dorothy Telfer
WILDFLOWERS OF ONTARIO
By Timothy Dickinson, Deborah Metsger, Jenny Bull, and Richard Dickinson
THE BOOK OF FIELD AND ROADSIDE
By John Eastman and Amelia Hansen
WILDFLOWERS OF OHIO
By Robert L. Henn
THE JOY OF WILDFLOWERS
By Millie B. House
By Linda Kershaw
DRINKS FROM THE WILDS
By Steven A. Krause
By Don Kurz
TALLGRASS PRAIRIE WILDFLOWERS
By Doug Ladd and Frank Oberle
NATIVE AMERICAN FOOD PLANTS
By Daniel E. Moerman
NATIVE AMERICAN MEDICINAL PLANTS
By Daniel E. Moerman
NEWCOMB’S WILDFLOWER GUIDE
By Lawrence Newcomb and Gordon Morrison
By Roger Tory Peterson and Margaret McKenny
By Donald and Lillian Stokes
NATIONAL AUDUBON SOCIETY FIELD GUIDE TO NORTH AMERICAN WILDFLOWERS (EASTERN REGION)
By John W. Thieret, William A. Niering, and Nancy C. Olmstead
EARTH MEDICINE EARTH FOOD
By Michael A. Weiner