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Conyza canadensis - (L.)Cronquist.

Common Name Canada Fleabane, Canadian horseweed
Family Asteraceae or Compositae
USDA hardiness 6-9
Known Hazards Skin contact with the plant can cause dermatitis in some people[222].
Habitats Light soils on waste and cultivated land, also on walls, avoiding acid soils in Britain[17].
Range N. America. Naturalized in Britain[17].
Edibility Rating    (1 of 5)
Other Uses    (1 of 5)
Weed Potential Yes
Medicinal Rating    (3 of 5)
Care (info)
Fully Hardy Well drained soil Moist Soil Semi-shade Full sun
Conyza canadensis Canada Fleabane, Canadian horseweed

Conyza canadensis Canada Fleabane, Canadian horseweed


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Physical Characteristics

 icon of manicon of flower
Conyza canadensis is a ANNUAL growing to 1 m (3ft 3in) by 0.5 m (1ft 8in).
See above for USDA hardiness. It is hardy to UK zone 7. It is in flower from June to October, and the seeds ripen from July to October. The species is monoecious (individual flowers are either male or female, but both sexes can be found on the same plant) and is pollinated by Bees, flies.
It is noted for attracting wildlife.
Suitable for: light (sandy) and medium (loamy) soils and prefers well-drained soil. Suitable pH: neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers dry or moist soil and can tolerate drought.

UK Hardiness Map US Hardiness Map


Erigeron canadensis.


 Cultivated Beds; East Wall. By. South Wall. By. West Wall. By.

Edible Uses

Edible Parts: Leaves
Edible Uses: Condiment

Young leaves and seedlings - cooked[105, 177]. Boiled, cooked in rice or dried for later use[183]. A nutritional analysis of the leaves is available[218]. The source of an essential oil that is used commercially for flavouring sweets, condiments and soft drinks[183]. The fresh leaves contain 0.2 - 0.66% essential oil[218].

References   More on Edible Uses

Figures in grams (g) or miligrams (mg) per 100g of food.
Leaves (Dry weight)
  • 0 Calories per 100g
  • Water : 0%
  • Protein: 14.9g; Fat: 1.8g; Carbohydrate: 75.1g; Fibre: 26.1g; Ash: 8.2g;
  • Minerals - Calcium: 1010mg; Phosphorus: 280mg; Iron: 0mg; Magnesium: 0mg; Sodium: 0mg; Potassium: 2610mg; Zinc: 0mg;
  • Vitamins - A: 0mg; Thiamine (B1): 0mg; Riboflavin (B2): 0mg; Niacin: 0mg; B6: 0mg; C: 0mg;
  • Reference: [ ]
  • Notes:

Medicinal Uses

Plants For A Future can not take any responsibility for any adverse effects from the use of plants. Always seek advice from a professional before using a plant medicinally.
Astringent  Diuretic  Dysentery  Emmenagogue  Homeopathy  Hypoglycaemic  Styptic  Tonic  
VD  Vermifuge

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[254]. Nowadays it is valued most for its astringency, being used in the treatment of gastro-intestinal problems such as diarrhoea and dysentery[254]. It is said to be a very effective treatment for bleeding haemorrhoids[254]. The whole plant is antirheumatic, astringent, balsamic, diuretic, emmenagogue, styptic, tonic and vermifuge[4, 7, 9, 21, 222]. It can be harvested at any time that it is in flower and is best used when fresh[4, 207, 238]. The dried herb should not be stored for more than a year[238]. The seeds can also be used[4]. An infusion of the plant has been used to treat diarrhoea and internal haemorrhages[213] or applied externally to treat gonorrhoea[213] and bleeding piles[7]. The leaves are experimentally hypoglycaemic[218]. The essential oil found in the leaves is used in the treatment of diarrhoea, dysentery and internal haemorrhages[4, 207, 218]. It is a uterine stimulant[213] and is also said to be valuable in the treatment of inflamed tonsils plus ulceration and inflammation of the throat[4]. A tea of the boiled roots is used to treat menstrual irregularities[213]. A homeopathic remedy is made from the plant[9]. It is used in the treatment of haemorrhoids and painful menstruation[9].

References   More on Medicinal Uses

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Other Uses


The plant contains small quantities of essential oil[7]. 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[7, 240].

Special Uses

Attracts Wildlife  Scented Plants

References   More on Other Uses

Cultivation details

Prefers a well-drained light or medium neutral to alkaline soil in a sunny position, though it tolerates most conditions[238]. 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[268]. 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[213]. The plant is used commercially as a food flavouring[183]. A good bee plant[200] but unfortunately it also harbours various insect pests such as the tarnished plant bug[1].

References   Carbon Farming Information and Carbon Sequestration Information

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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.

Other Names

If available other names are mentioned here

Canadian fleabane. horseweed. Spanish: erigeron del Canada; escoba dura; hierba de caballo; hierba impia; olivarda. French: erigéron du Canada; vergerette du Canada. Portuguese: avoadinha. Canada: mare's tail. Colombia: cvenadillo. Cuba: conyza; zancarana. France: erigeron de Canada; vergerette de Canada. Germany: Kanadischer berufkraut; Kanadisher katzenschweif. India: jarayupriya. Iraq: thail el-faras. Italy: impi; saeppola. Japan: himemukashiyomogi. Madagascar: sarijamala. Mauritius: herbe gandi. Mexico: pegajosa. Netherlands: fijnstraal, Canadeese. Norway: canadese fijnstraal; hestehamp. Poland: przymiotno kasnadyjskie. Puerto Rico: pascueta; rozuz. South Africa: armoedskruid; kanadese skraalhans. Spain: altabaca; canem bord; erigeron de Canada; zamarraga. Sweden: kanadabinka. Turkey: sifa out. USA: butterweed; Canada horseweed; fireweed; hogweed. Yugoslavia (Serbia and Montenegro): repusnjaca.

Found In

Countries where the plant has been found are listed here if the information is available

Native throughout most of North America and Central America. It is also widely naturalized in Eurasia and Australia.

Weed Potential

Right plant wrong place. We are currently updating this section. Please note that a plant may be invasive in one area but may not in your area so it’s worth checking.

A common weed in temperate to tropical regions.

Conservation Status

IUCN Red List of Threatened Plants Status : This taxon has not yet been assessed.

Related Plants
Latin NameCommon NameHabitHeightHardinessGrowthSoilShadeMoistureEdibleMedicinalOther
Inula conyzaPloughman's SpikenardBiennial/Perennial1.2 5-9  LMHNM012

Growth: S = slow M = medium F = fast. Soil: L = light (sandy) M = medium H = heavy (clay). pH: A = acid N = neutral B = basic (alkaline). Shade: F = full shade S = semi-shade N = no shade. Moisture: D = dry M = Moist We = wet Wa = water.


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