What is a common characteristic of postemergence herbicides?

Postemergence herbicides are designed to control weeds after they have emerged from the soil. A defining characteristic of these herbicides is their effectiveness when weeds are in an active growth phase. This is because active growth enhances the absorption and translocation of the herbicide within the plant, leading to improved efficacy in controlling the weeds.

In contrast, if weeds are not actively growing, perhaps due to environmental stress or dormancy, the uptake of the herbicide can be significantly reduced, making it less effective. Therefore, using postemergence herbicides when weeds are growing vigorously ensures the best results in managing unwanted plant growth in agricultural or landscaped areas.