(Radio Iowa) – An Iowa State University agronomy professor says erratic Midwest weather that’s veered from drought conditions to excessive rain is fueling toxic weed growth in pastures — including plants that are poisonous to cattle. Shelby Gruss says it’s important to keep a healthy stand of grasses in low-lying areas where water tends to pool after a heavy rain.
“I think about weeds as opportunistic. If we have a spot that’s bare, that’s where you’re going to see them pop up,” Gruss said. “Poison hemlock, it likes moist soils.” The entire Poison Hemlock plant is toxic and it can be deadly to cattle even in small amounts. Gruss says livestock farmers need to be on the lookout for other toxic vegetation like St. John’s Wort, Johnson Grass and Wild Parsnip.
Queen Anne’s Lace, while not poisonous, looks like Poison Hemlock and many farmers remove it because it does not provide as much nutrition to livestock as other forage. Gruss, who is a forage specialist for I-S-U Extension, has a note of caution about handling Queen Anne’s Lace. “It’s really important to be able to identify this one,” Gruss says, “because if you are trying to remove it, you need to wear gloves and long sleeves when handling it.” If the sap of the plant touches skin, it can cause a painful rash similar to a second-degree sunburn.
Under state law, county officials have the authority to order the destruction of 25 types of noxious weeds to stop the spread into neighboring properties.
