Ambrosia trifida
(Giant Ragweed)

Other pictures of this plant:

               Seedpod                                           Leaf                                            Stem                                        Seed                                          Habit

Facts About this Plant:

    Common Names: Giant Ragweed, Horse-Cane, Big Bitterweed, Tall Ambrosia, Crown Weed, Great Ragweed, Texan Great Ragweed, Tall Ragweed, Blood Ragweed, Horseweed, Buffaloweed, Kinghead
    Lifespan: Annual
    Zones: N/A
    Type: Forb
    Bloom Time: June - September
    Status: Native

Ambrosia trifida, or Giant Ragweed, is native to the eastern three quarters of the continental United States, and is considered adventive in the other western quarter . It is an annual, which grows in fields, prairies, along trails, and along woodland edges, as well as in open woods, disturbed areas, railroads and waste places. It blooms in mid to late summer with small green-yellow flowers. This plant is responsible for many of the allergies people experience in the summer and fall and not, as is often thought, Goldenrod (Solidago) species.

There are several plants in this genus, but only three are very widely distributed: Ambrosia artemisiifolia, Ambrosia psilostachya, and Ambrosia trifida. Ambrosia trifida can be pretty easily identified by its lobed leaves, usually in either three or five lobes. Also, it can be quite tall, which can also be a clue to identification. See comparison photo. More information on other species will be posted later.

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