Weed List

                                                                       ND Noxious & Troublesome Weeds       

Swamp ragwort
[Senecio congestus (R. Br.) DC]

State Noxious Weed List -No

Growth form: Generally an annual, rarely biennial, shrub native to the northern Great Plains. Grows 3 to 4 feet tall along marshes, stream banks, and slough areas. The flowers are bright yellow in umbels of 6 to 12 or more heads. Each flower is about 0.15 to 0.5 inches across. The leaves are oblong, toothed and clasp the stem generally 5 to 6 inches long. The stems are hollow and pubescent. The plant flowers from May to early-July. The achenes have long pappus-hairs which are quite noticeable. The seed are thought to be spread by waterfowl.

The genus Senecio is found world-wide and contains about 3,000 species which range from tropical trees to succulents to arctic herbs.

Swamp ragwort has been increasing in frequency recently and infestations should be monitored even though the plant generally is not considered invasive.
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