Which type of herbicide is effective against both grass and broadleaf weeds?

The most appropriate choice is a non-selective herbicide. Non-selective herbicides are designed to kill or control a wide range of plant species, including both grassy and broadleaf weeds. This makes them particularly useful in situations where complete vegetation removal is desired, such as site preparation for replanting or when dealing with invasive species.

In contrast, selective herbicides target specific types of plants, usually distinguishing between grass weeds and broadleaf plants, allowing one to remain unharmed while eliminating the other. Pre-emergent herbicides work before weeds emerge, preventing germination rather than killing existing plants. Residual herbicides, meanwhile, remain in the soil to affect future plant growth but do not specifically target plants at the surface level. Thus, non-selective herbicides are the preferred choice for effectively managing both types of weeds simultaneously.