Pest Profile

Bur Ragweed
Ambrosia grayii

Pest Description

A perennial, reproducing by underground root-stocks and seeds. Plant erect, 1 to 2 feet high, somewhat bushy, usually branching from the base and covered with fine, woolly hairs. The plant is purplish-white in appearance and grows from a well developed root system.

Leaves alternate, or opposite, broadly ovate, pinnately 3-5 parted or entire, long-petioled, dusty white in color. The end segment of the leaves much larger than the other segments.

Male flowers are in small drooping heads at the top of the plant and female flowers are in the axil of the leaves, usually one per leaf. Flowers in composite heads in short racemes. Seed cone shaped in heads 3-7 mm. long, with hooked spines or curved at tip. Seeds, September through November.

Taken from State of Kansas:

Pest photo source

Curtis Thompson, K-State Research and Extension