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Ambrosia - L.

Common Name Roman Wormwood, Bitterweed, Blackweed, Carrot Weed, Hay Fever Weed, Stickeweed, Tassel Weed, Wild Ta
Family Asteraceae or Compositae
USDA hardiness 4-8
Known Hazards The pollen of this plant is a major cause of hayfever in N. America[207, 222]. Ingesting or touching the plant can cause allergic reactions in some people[222].
Habitats Waste places in Western N. America[60]. Found in dry soils, it can become a pernicious weed in cultivated soils[235].
Range N. America - British Columbia to Nova Scotia and Florida. Locally established casual in Britain[17].
Edibility Rating    (2 of 5)
Other Uses    (1 of 5)
Weed Potential Yes
Medicinal Rating    (3 of 5)
Care (info)
Fully Hardy Moist Soil Semi-shade Full sun
Ambrosia Roman Wormwood, Bitterweed, Blackweed, Carrot Weed, Hay Fever Weed, Stickeweed, Tassel Weed, Wild Ta


http://www.hear.org/starr/
Ambrosia Roman Wormwood, Bitterweed, Blackweed, Carrot Weed, Hay Fever Weed, Stickeweed, Tassel Weed, Wild Ta
http://www.hear.org/starr/

 

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Summary

Bloom Color: Green. Main Bloom Time: Early fall, Late summer, Mid summer, Mid fall. Form: Upright or erect. Other Names : Annual Ragweed, Bitterweed, Blackweed, Carrot Weed, Hay Fever Weed, Roman Wormwood, Stammerwort, Stickweed, Tassel Weed, Wild Tansy, and American Wormwood.


Physical Characteristics

 icon of manicon of flower
Ambrosia is a ANNUAL growing to 0.9 m (3ft) by 0.2 m (0ft 8in) at a medium rate.
See above for USDA hardiness. It is hardy to UK zone 4. It is in flower from August 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 Wind.
Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: mildly acid, neutral and basic (mildly alkaline) soils. It can grow in semi-shade (light woodland) or no shade. It prefers moist soil.

UK Hardiness Map US Hardiness Map

Synonyms

A. elatior.

Plant Habitats

Edible Uses

An oil is obtained from the seed. It has been suggested for edible purposes because it contains little linolenic acid[61, 183]. The seed contains up to 19% oil[61], it has slightly better drying properties than soya bean oil[183].

References   More on Edible Uses

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.


The leaves are very astringent, emetic and febrifuge[222, 257]. They are applied externally to insect bites, rheumatic joints and various skin complaints, internally they are used as a tea in the treatment of fevers, pneumonia, nausea, intestinal cramps, diarrhoea and mucous discharges[222, 257]. Juice from the wilted leaves is disinfectant and is applied to infected toes[257]. A tea made from the roots is used in the treatment of menstrual disorders and stroke[222]. The pollen is harvested commercially and manufactured into pharmaceutical preparations for the treatment of allergies to the plant[222].

References   More on Medicinal Uses

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Other Uses

There is some indication it has been used as a disinfectant and Oil.

Special Uses

References   More on Other Uses

Cultivation details

We have very little information on this species but suggest growing it in a sunny position in a well-drained soil. It has been suggested for commercial cultivation[61]. Some plants produce mainly sterile heads[60]. The pollen from the flowers of this species is an important cause of hay-fever in N. America[17]. Special Features:North American native, Invasive, Inconspicuous flowers or blooms.

References   Carbon Farming Information and Carbon Sequestration Information

Temperature Converter

Type a value in the Celsius field to convert the value to Fahrenheit:

Fahrenheit:

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Plants For A Future have a number of books available in paperback and digital form. Book titles include Edible Plants, Edible Perennials, Edible Trees,Edible Shrubs, Woodland Gardening, and Temperate Food Forest Plants. Our new book is Food Forest Plants For Hotter Conditions (Tropical and Sub-Tropical).

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Plant Propagation

Seed - we have no details for this species but suggest sowing the seed in situ in April.

Other Names

If available other names are mentioned here

Native Range

Coming Soon

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.

It is listed as a noxious weed in Illinois (common ragweed) and Oregon (ragweed)as a "B" designated weed. Ragweed is a very competitive weed and can produce yield losses in soybeans as high as 30%. Control with night tillage reduces emergence by around 45%. Small grains in rotation will also suppress common ragweed if they are overseeded with clover. Otherwise, the ragweed will grow and mature and produce seed in the small grain stubble.

Conservation Status

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

Related Plants
Latin NameCommon NameHabitHeightHardinessGrowthSoilShadeMoistureEdibleMedicinalOther
Ambrosia artemesiifoliaRoman Wormwood, Bitterweed, Blackweed, Carrot Weed, Hay Fever Weed, Stickeweed, Tassel Weed, Wild TaAnnual0.9 4-8 MLMHSNM231
Ambrosia trifidaGiant Ragweed, Great ragweed, Texan great ragweed, Bitterweed, Bloodweed, Buffalo Weed, Horse CaneAnnual2.0 1-11 MLMHSNM131

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.

 

Expert comment

Author

L.

Botanical References

60235

Links / References

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