Species Specifics: Snow-on-the-Mountain

Fast facts

Snow-on-the-mountain is part of the spurge family and contains a sap that is toxic to livestock and humans.
Cattle typically won’t graze it, but this weed has been associated with health complications and stress in livestock, leading to decreased weight gain and profitability.
The weed remains toxic in hay where cattle can’t be as selective. It’s a weed worthy of control.

What to look for

Snow-on-the-mountain (Euphorbia marginata) is an annual plant in the spurge family. It reaches heights of 2 to 4 feet and has oblong, light green and white leaves. Its “flowers” are several white bracts (leaflike structures) clustered at the top.

Where it is found

Snow-on-the-mountain is native to much of the United States and was regarded as an ornamental plant, but its growth habits caused it to spread to areas where it’s unwanted. It tolerates most soil types but prefers shaded areas — it’s commonly found near fence lines and trees. It spreads by underground rhizomes. Mechanical control is not recommended because broken-off pieces of rhizomes can quickly form new plants and expand infestations.

How to treat it

Cattle typically will not graze snow-on-the-mountain because of its bitter taste but will if desirable forage is scarce, such as during drought. If the land is hayed, livestock are not able to be as selective. You should prioritize removing this weed in pastures before grazing and in hayfields before harvesting because its milky sap causes skin, mouth and digestive tract irritation if consumed.

“While cattle rarely die from consuming snow-on-the-mountain, the health complications and stress associated with it reduce weight gain, performance and profitability,” says Dr. Sam Ingram, a field scientist for Corteva Agriscience.

To control snow-on-the-mountain, apply 16 to 20 fluid ounces of DuraCor^® herbicide with 1% v/v methylated seed oil per acre or 20 to 32 fluid ounces of GrazonPD3™ herbicide per acre. Treat when plants are 12 inches or taller. Do not apply after bloom.

GrazonPD3 is a federally Restricted Use Pesticide. GrazonPD3 is not for sale, distribution or use in Nassau and Suffolk Counties in New York State. Always read and follow label directions. Under normal field conditions, DuraCor® is nonvolatile. DuraCor has no grazing or haying restrictions for any class of livestock, including lactating dairy cows, horses (including lactating mares) and meat animals prior to slaughter. Label precautions apply to forage treated with DuraCor and GrazonPD3 and to manure and urine from animals that have consumed treated forage. DuraCor is not registered for sale or use in all states. Contact your state pesticide regulatory agency to determine if a product is registered for sale or use in your state. Consult the label for full details. Always read and follow label directions.