What characteristic defines a systemic herbicide?

A systemic herbicide is characterized by its ability to be absorbed by a plant and then translocated throughout its tissues, allowing it to affect various parts of the plant, including roots and stems, not just the leaves. This property is crucial because it enables the herbicide to kill the entire plant rather than just the part that was exposed to the chemical. By moving through the plant's vascular system, systemic herbicides can reach areas that are not directly touched upon application, thus ensuring a more thorough treatment of the target plant.

The systemic nature of these herbicides makes them particularly effective against perennial weeds and those that have established root systems. This characteristic distinguishes systemic herbicides from contact herbicides, which only disrupt the area they directly contact and are typically less effective on plants with extensive root systems. Understanding this key feature is important for proper herbicide application and management in various agricultural and landscaping practices.