Species Specific: Ironweed

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The story goes: Ironweed gets its name because it’s so difficult to pull up or even dig up with a spade. Ironweed, both tall and western, can be tough to control, but the task gets easier with DuraCor® herbicide.

What to look for

Tall and western ironweed (Vernonia gigantea and baldwinii) are clump-forming perennials in the sunflower family. Ironweed is known for its fluffy-looking clusters of purple flowers and dark red stems. Tall ironweed’s tough erect stems can grow up to 10 feet tall and can be hairy. Western ironweed typically is 3 to 5 feet tall. Long, lance-shaped leaves are sharply toothed with short hairs on the lower surface. Ironweed blooms from July to October.

Where it is found

Ironweed is common throughout the United States, but western ironweed is most common in the Midwest and the South. Tall ironweed can be found in the Midwest, South and along the east coast of the United States and in southeastern Canada.

Ironweed prefers moist soils, and it is especially common in pastures and hayfields. Because its unpalatable, cattle do not eat it. Like with other troublesome weeds, this reduces grazing efficiency — cattle spend too much time looking for grass rather than eating it — and land utilization but increases spot grazing.

How to treat

Ironweed spreads by seed and rhizomes. A single tall ironweed plant can produce 12,000 seeds in one season. Ironweed also has an extensive fibrous root system, which makes mechanical eradication nearly impossible and means leaving any part of the root behind will result in regrowth.

For best control, apply DuraCor® herbicide at least 12 fluid ounces per acre during the vegetative state prior to bloom. Use higher rates in labeled rate range — 16 to 20 fluid ounces per acre — when weeds are larger, after bloom or if you want longer residual control.

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 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. 


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