The wildflower ragwort (Senecio jacobaea) is a real danger to farm animals. This weed contains pyrrolizidine alkaloids, which are toxic to horses, sheep and cattle, plus wild animals such as deer. Ragwort is a prolific grower, spreading rapidly and producing up to 150,000 seeds per plant. According to the Surrey County Council, ragwort seeds can lie dormant in soil for up to two decades. Fortunately, there are broad-leaf herbicides that can tame this noxious weed. The key is to start control efforts before the plant forms seeds.
Weedmaster is a selective, postemergent 2,4-D herbicide containing dimethylamine salt. According to manufacturer BASF, Weedmaster herbicide can be used to kill broadleaf weeds, including ragwort, on fallow systems between crop applications, general farmstead, pastures, rangeland, sugarcane, sorghum, sillage and hay grass, and wheat.
All-In-One Weed Killer
Bayer's All-In-One Lawn Weed & Crabgrass Killer is a post-emergent, selective herbicide containing dimethylamine salt, Quinclorac and Dicamba. It kills more than 200 broad-leaf and grassy weeds, including ragwort, without injuring lawn grasses.
Banvel is an agricultural herbicide containing diglycolamine salt. Made by Micro Flo, Banvel is used to kill broad-leaf weeds--including ragwort--in pastures and rangeland grasses, red fescue, corn, cereals and blueberries. It can injure some desirable trees and plants, including cotton, flowers, fruit trees, beans, peas, grapes, potatoes, sunflowers, tomatoes and other broad-leaf plants.