Ragweed - Ambrosia artemisiifolia


    Medium to tall plant, not aromatic. Stems branched and angled, often reddening and becoming somewhat woody below. Leaves mostly opposite, greyish below usually pinnately lobed with lanceolate divisions. Male Flowerheads greenish tallow 3 to 5 mm in slender spikes. Female flowers inconspicuous below, at the base of the upper leaves. Flower bracts with spiny teeth.

    Similar Species

    Other Ambrosia have been recorded in Britain, and may turn up

    Identification difficulty
    ID guidance

    Annual.  Leaves pinnately divided; female phyllaries in fruit with small erect spines near or above the middle

    Recording advice

    A photo of the whole plant, showing leaves as well as flowers and fruits.


    Disturbed ground

    When to see it

    August to October

    Life History


    UK Status

    Not common in Britain.

    VC55 Status

    Uncommonn in Leicestershire and Rutland. In the 1979 Flora survey of Leicestershire it was found in only 2 of the 617 tetrads.

    In the current checklist (Jeeves 2011) it is listed as Alien; casual; disturbed ground; rare.

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    Leicestershire & Rutland Map

    MAP KEY:

    Yellow squares = NBN records (all known data)
    Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

    UK Map