Higher rates may be required in high-rain areas. Soil residues are normally for one winter in western Oregon. Dicamba will damage or eliminate clovers when applied to pastures. Picloram is both a foliar and soil active herbicide. It will not kill perennial grasses when used according to the label.
Most formulations are restricted-use herbicides.
Do not contaminate wate r. Potatoes, beans, and many other broadleaf crops are very sensitive to picloram. Do not use in diversified cropping areas. Do not graze dairy animals on treated areas within 2 weeks after application. For broadcast treatment. Apply when thistles are actively growing but past the bud growth stage.