Giant Ragweed

Plant Info

Also known as:	Great Ragweed, Horseweed
Scientific name:	Ambrosia trifida
Family:	Aster (Asteraceae)
Life cycle:	annual
Origin:	native
Habitat:	sun or part shade; fields, along roads, edges of woods
Bloom season:	late summer
Plant height:	3 to 12 feet
Spotted in Ramsey County at:	Long Lake Regional Park Rice Creek Trail Corridor Vadnais/Snail Lake Regional Park

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Detailed Information

Flower:

Narrow 3 to 8-inch spike of yellowish green flowers on short stems. Individual flowers are 1/8 inch across and have no petals. One plant may have several spikes.

Leaves:

Leaves have serrated edges and can be very large—up to 12 inches long and 8 inches wide. The largest leaves have 3 to 5 lobes with pointed tips; the smaller leaves are unlobed and pointed on both ends. Attachment is opposite.

Notes:

This plant is the cause of much suffering during hay fever season.

More photos

• close-up of flowers
• full plant, about 4 feet tall

More green wildflowers. All photos taken at Long Lake Regional Park in New Brighton, MN, August 2006.

Comments

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