Which type of herbicide is typically used on perennials?

Systemic herbicides are specifically designed to be absorbed by the plant and travel throughout its system. This is particularly effective for perennials, which are characterized by their ability to survive multiple growing seasons and have extensive root systems. By using systemic herbicides, applicators can target the underground parts of the plant, including roots, making it a more effective method for eliminating well-established perennial weeds.

Preemergence herbicides, on the other hand, are formulated to prevent the germination of seeds. They work best on annual weeds and are not effective against existing perennial plants. Contact herbicides are intended to kill the parts of the plant they directly touch but do not affect the plant's root system, which means they're less effective on perennials that can regrow from roots or underground parts. Herbicides with rapid degradation tend to break down quickly in the environment, limiting their longevity and efficacy, especially on persistent weeds, which often require a longer-lasting solution like that provided by systemic herbicides.