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Common Name: Canada Fleabane

General Information

Conyza canadensis is an annual plant that can grow up to 1.00 metres tall.
It is harvested from the wild for local use as a food, medicine and source of materials.

Known Hazards

Skin contact with the plant can cause dermatitis in some people[].

Botanical References

Range

N. America - in virtually all mainland states. Naturalized in Britain[].

Habitat

Light soils on waste and cultivated land, also on walls, avoiding acid soils in Britain[].

Properties

Edibility Rating
Medicinal Rating
Habit	Annual
Height	1.00 m
Pollinators	Bees, Flies
Cultivation Status	Wild

Cultivation Details

Prefers a well-drained light or medium neutral to alkaline soil in a sunny position, though it tolerates most conditions[].
Originally from N. America, Canada fleabane has become naturalized in many areas of the world and is considered to be a nuisance weed in many areas[]. The plant is very adaptable to differing conditions and can vary dramatically in height, from only a few centimetres in poor soils to as much as 3 metres tall in rich soils[].
The plant is used commercially as a food flavouring[].
A good bee plant[] but unfortunately it also harbours various insect pests such as the tarnished plant bug[].

Edible Uses

Young leaves and seedlings - cooked[, ]. Boiled, cooked in rice or dried for later use[]. A nutritional analysis of the leaves is available[].
The source of an essential oil that is used commercially for flavouring sweets, condiments and soft drinks[]. The fresh leaves contain 0.2 - 0.66% essential oil[].

Medicinal

In traditional North American herbal medicine, Canada fleabane was boiled to make steam for sweat lodges, taken as a snuff to stimulate sneezing during the course of a cold and burned to create a smoke that warded off insects[]. Nowadays it is valued most for its astringency, being used in the treatment of gastro-intestinal problems such as diarrhoea and dysentery[]. It is said to be a very effective treatment for bleeding haemorrhoids[].
The whole plant is antirheumatic, astringent, balsamic, diuretic, emmenagogue, styptic, tonic and vermifuge[, , , , ]. It can be harvested at any time that it is in flower and is best used when fresh[, , ]. The dried herb should not be stored for more than a year[]. The seeds can also be used[].
An infusion of the plant has been used to treat diarrhoea and internal haemorrhages[] or applied externally to treat gonorrhoea[] and bleeding piles[]. The leaves are experimentally hypoglycaemic[].
The essential oil found in the leaves is used in the treatment of diarrhoea, dysentery and internal haemorrhages[, , ]. It is a uterine stimulant[] and is also said to be valuable in the treatment of inflamed tonsils plus ulceration and inflammation of the throat[].
A tea of the boiled roots is used to treat menstrual irregularities[].
A homeopathic remedy is made from the plant[]. It is used in the treatment of haemorrhoids and painful menstruation[].

Other Uses

The plant contains small quantities of essential oil[]. Since the plant is readily obtainable, extraction of the oil is feasible - it has a special quality that would make it suitable in the making of perfumes with unusual nuances[, ].

Propagation

Seed - we have no information on this species but suggest sowing the seed in spring in situ. An autumn sowing in situ might also be worthwhile.