Solidago canadensis, known as Canada goldenrod or Canadian goldenrod, is an herbaceous perennial plant of the family Asteraceae. It is native to northeastern and north-central North America. It is an invasive plant in other parts of the continent and several areas worldwide, including Europe and Asia. It is often grown as an ornamental in flower gardens.
The plant is erect, often forming colonies. Flowers are small yellow heads held above the foliage on a branching inflorescence.
Ecology and distribution
Solidago canadensis is sometimes browsed by deer and is good to fair as food for domestic livestock such as cattle or horses.
It is found in a variety of habitats. It typically is one of the first plants to colonize an area after disturbance (such as fire) and rarely persists once shrubs and trees become established. It is found in very dry locations and also waterlogged ones.
Although utilized by a variety of insects to some degree for its floral rewards, it is especially strongly favored as a nectar source by paper wasps, such as Polistes parametricus and Polistes fuscatus.  Aside from wasps, it is also fairly popular with honeybees and bumblebees. It is generally passed over by monarchs and other larger-sized butterflies, in favor of other flowers.
It can be extremely aggressive and tends to form monocultures and near-monocultures in parts of its native range, such as in Southwest Ohio clay loam. It often outcompetes competitive species in such habitat. It not only seeds a great deal but also spreads rapidly via running rhizomes. Its root system is very tough and plants that have been pulled out of the ground prior to freezing and left exposed atop soil have survived -14 Fahrenheit (-26C) winter temperatures.
Usually a large monoculture of yellow flowers in early-fall is a sure sign that you are dealing with Canada goldenrod. These colonies can exclude all other plant growth and grow to a substantial size, making them a concern for land managers.— Frank Hassler
In eastern and southeastern China, particularly the provinces of Zhejiang, Jiangsu, Jiangxi and Shanghai, its invasion has caused widespread concern. It has been reported that the spread of invasive plants including Canada goldenrod has caused the extinction of 30 native plants in Shanghai. In the city of Ningbo, Zhejiang, it has reduced local orange harvests. It is still spreading across China, and sightings have been reported in as far as Yunnan province.
The stems and leaves of goldenrod have been dried and used in folk medicine. Its main use has been on the skin to treat wounds and as a diuretic. It has been used to get rid of kidney stones and other kidney ailments by flushing them out. Other uses have included as a mouth rinse and gargle, and treatment for inflammation, tuberculosis, allergies, gout, hemorrhoids, arthritis, asthma, internal bleeding. Animal testing has shown it to be effective in reducing hypertension, muscle spasms, and inflammation, as well as fighting infections. It contains alkaloids that can mask bitterness, possibly making it an alternative to artificial substances or licorice allergies in medicinal combinations.
Allergic skin reactions can occur when coming into contact with the living plant. However, it is generally recognized that the plant does not cause allergic rhinitis. It is often confused with ragweed, which does cause pollen allergies.
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- title = Complementary and Alternative Medicine - Penn State Hershey Medical Center - Goldenrod
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|Wikiversity has bloom time data for Solidago canadensis on the Bloom Clock|
- Jepson Manual Treatment: Solidago canadensis
- United States Geological Survey: Solidago canadensis
- Profile: Canada Goldenrod (Solidago canadensis) Photos, Drawings, Text. (Wild Plants of Winnipeg from Nature Manitoba)