Weed of the Week

8-25-08

Ragweed, Ambosia artemisiifolia

                 

Photo credits: Rob Lum @ NDSU

 Characteristics:

Family: Asteraceae (Sunflower family)

Origin: Native to North America

Description:

• Native reaching four feet in height

• Many branched plant arising from a single stem

Stems:

• Blue green

• Erect

Flowers:

• Flowers spike at terminal branches

• Male flowers and female flowers separate at the top of the flower spike

• Flowering occurs in late summer with seed production in October

Leaves:

• Blue green

• Pinnately divided

• Both alternate and opposite

 

Fruit:

• Awl shaped with a spiny projection

 

Additional information:

This annual is common throughout the United States and causes Hay Fever and is considered troublesome for this reason.  Found commonly along ditches and waste areas.

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