How do I control thistles in my pasture?
I have received a question or two about thistle control in pastures. Thistles are biennials, which grow from seed in year one and produce seed in the second year. During the first year, the plant will grow as a rosette and the second year the plant bolts from the rosette stage. Most thistles I see in area pastures are Yellow thistle, also known as horrible thistle (Cirsium horridulum). Yellow thistle has large, clustered flower heads with spiny, feathery bracts that almost enclose each flower’s entire head. Flowers are yellow or reddish purple and rarely white. Stems are covered in fine hairs and hairlike projections.
A single thistle plant can produce at least 4,000 seed so managing the seed bank is important for controlling this pest.
How do I Control it? Mowing can effective if it is timed during late bolting stage of development. The stalk is typically hollow during this time. If you mow thistles during the rosette stage you will be disappointed in the level of control.
Information from University of Florida indicate that good thistle control (>90 %) can be obtain by applying herbicides such as 2,4-D, Metsulfuron, Remedy, Weedmaster, GrazonNext and Pasturegard during the rosette stage of development.
What is this weed in my pasture? I received a question or two about this weed in a pasture. According to Dr. Patrick McCullough, UGA Forage Specialist, the weed in question was Mayweed Chamomile (Anthemis cotula). Below is an example of Mayweed. If you would like more information on Mayweed please go to the link https://wiki.bugwood.org/HPIPM:Mayweed_chamomile
If you have any more questions please contact your local county Extension agent.