Giant ragweed
June 11, 2015
Print
EmailAmbrosia trifida L. Asteraceae (Aster family)
Life cycle
Erect, branching summer annual.
Young giant ragweed plant.
Leaves
Cotyledons are thick and oval to spatula-shaped and differ from those of common ragweed by being three to four times larger. Initial leaves are entire; successive leaves have three to five lobes and leaves are opposite in arrangement. Leaves are hairy and rough.
Giant ragweed seedling (left) and leaf (right).
Stems
Usually hairy and rough to touch, erect and branched and up to 15 feet in height.
Flowers and fruit
Flowers are generally inconspicuous, found on terminal branches. They produce prolific amounts of pollen. The seed is enclosed in a single-seeded, woody fruit with five spikes encircling a long point, resembling a crown. Seeds are found in the axils of the upper leaves
Giant ragweed flowering branch.
Reproduction
Seeds.
Print a PDF of this page: Giant ragweed
Other Documents in this Series
You Might Also Be Interested In
-
MSU named Top 10 agriculture and forestry college in new report
Published on March 23, 2021
-
Protecting Michigan’s environment and wildlife through the Conservation Reserve Enhancement Program
Published on September 1, 2021
-
Michigan Sea Grant approaches Great Lakes issues with a statewide outlook and a strong local focus
Published on August 23, 2021
-
MSU research team receives USDA grant to evaluate effectiveness, cost of new blueberry pest management strategies
Published on February 19, 2021
-
Inspired and in-person: face-to-face programming returns for Michigan 4-H
Published on August 25, 2021
-
Creating innovative models to assess spread, possible management of deadly chronic wasting disease
Published on February 1, 2021
Accessibility Questions:
For questions about accessibility and/or if you need additional accommodations for a specific document, please send an email to ANR Communications & Marketing at anrcommunications@anr.msu.edu.