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PERENNIAL SOWTHISTLE
Perennial sowthistle is a creeping perennial that reproduces by seeds and horizontal roots. It is comforting to know that the seeds of this plant do not remain viable in the soil for as long as other noxious weeds. The root is what makes this plant so aggressive. You can find this weed growing in gardens, crops, along ditchbanks, and fertile waste areas. All plant parts are filled with a bitter, milky juice. It can grow 2 to 4 feet tall. The widely spreading white underground root can penetrate depth of up to 10 feet.
Control
Mechanical: Fire will kill the top growth, but it will have little effect on the underground portion of the plant. Cultivation is most efficient when emerging shoots are at the 6-leaf rosette stage.
Biological: Two gall-forming flies native to Europe are being studied as a possible control option. Tephritis dilacerata forms galls on the flower heads to limit seed production. Perennial sowthistle is acceptable as livestock feed, although not highly preferred. Palatability is rated as poor to fair for cattle, sheep, and horses. It is relatively unpalatable to lambs. Grazing and repeated cultivation can help reduce stands by depleting root energy reserves
Herbicides: Few herbicides are available for effective control of perennial sowthistle. Products containing dicamba or 2,4-D can be used for suppression. In rangeland, pastures, roadsides, and other non-crop areas, product-containing clopyralid has proven the most effective. It can also be used in a crop situation, if care is taken to complement your rotation schedule.
When choosing any kind of control method, assure that your choice is suited for your particular situation. Always read and follow the entire product label before applying any herbicide. |