Rayless goldenrod (Isocoma pluriflora), also known as jimmyweed, is an erect, bushy, unbranched perennial shrub growing from a woody root crown, growing 2 to 4 feet tall. New stem growth is gray to white, hairless and shiny. The leaves are alternate, linear and sticky. Yellow flowers grow in clusters on stem tips from June to October.
The plant dies back to ground level each winter, and regrowth starts from the root crown beginning early the following spring.
Rayless goldenrod is native to southern Colorado into Texas, New Mexico and Arizona. It is often found on dry rangelands, especially in river valleys, along drainage areas and irrigation canals.
Because of the unpalatability of rayless goldenrod, cattle will typically not graze it, except during a drought or if land has been overgrazed. The importance of controlling rayless goldenrod is twofold: Control redirects valuable nutrients to desirable grasses and protects your herd from the weed’s toxic properties. Rayless goldenrod contains tremetol in both green and dry material. Tremetol is toxic to all livestock, and it produces a condition known as “trembles.” Daily consumption of only 1% to 1.5% of an animal’s body weight can produce poisoning symptoms or even cause death.
Protect your herd by treating rayless goldenrod with Tordon 22K. For best control, apply 1 to 2 pints of Tordon 22K per acre after bloom but prior to the first hard frost.
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