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Weed Identification in Christmas Trees

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Common ragweed - Ambrosia artemisiifolia L.
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Common ragweed leaf Common ragweed flowering branch
Common ragweed leaf. Common ragweed flowering branch.
Common ragweed seedling
Common ragweed seedling.

Life cycle: Erect, branching summer annual.

Leaves
: Cotyledons are thick and oval to spatula-shaped. Leaves are fernlike, once or twice compound and usually hairy. Upper leaves are alternate; lower leaves may be opposite or alternate with distinct petioles.

Stems
: Usually hairy, erect and branched up to 6 feet tall.

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 several spikes resembling a crown.

Reproduction
: Seeds.
Similar weeds: Giant ragweed (A. trifida L.) Differs by having cotyledons three to four times larger; three- to five-lobed leaves opposite in arrangement; and a height that may reach 15 feet.

Western ragweed (A. psilostachya DC.) Differs by having a perennial nature with prolific creeping roots, densely hairy leaves and a height typically not above 4 feet.
Giant ragweed seedling Giant ragweed leaf Western ragweed seedling Western ragweed leaf
Giant ragweed seedling and leaf. Giant ragweed leaf. Western ragweed root sprout and leaf. Western ragweed leaf.
The MSU IPM Program maintains this site as an access point to pest management information at MSU. The IPM Program is administered within the Department of Entomology, fueled by research from the Michigan Agricultural Experiment Station, delivered to citizens through MSU Extension, and proud to be a part of Project GREEEN.
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02/07/08