Ragweed, Ambrosia artemisiifolia


Short description of Ambrosia artemisiifolia, Ragweed

A tall annual herb (up to 1.2m) with a stout central stem and lateral side branches. The leaves are opposite at the base and become alternate towards in the inflorescence. The leaves are deeply divided (bipinnatifid) reaching about 15 cm long, with an ovate outline. The plant is dioecious with abundant male flowers on the branches and fewer female flowers at the base of the inflorescence. Flowers appear in August-October.

Description of Ambrosia artemisiifolia, Ragweed status in GB

Ragweed is a common seed contaminant that has not naturalised, but might if the climate warms.

Habitat summary: Ambrosia artemisiifolia, Ragweed

In countries where it is native or naturalised it grows as a weed of crops, along river banks, in wasteplaces and along roadsides.

Overview table

Environment: Terrestrial
Species status: Non-Native
Native range: Northern America, Alberta, British Columbia, Labrador, Manitoba, New Brunswick, Nova Scotia, Ontario, Saskatchewan, Yukon
Functional type: Land plant
Status in England: Non-Native
Status in Scotland: Non-Native
Status in Wales: Non-Native
Location of first record: v.c.16
Date of first record: 1836

Distribution map

GB Distribution from NBN Atlas

Author's name:

Quentin Groom

Last updated:

November 27th 2015

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