What should be the primary concern when applying herbicides around trees and shrubs?

When applying herbicides around trees and shrubs, the primary concern should be the potential for drift and the root system extension of these plants. Drift occurs when the herbicide particles or droplets are carried away from the target application area by wind, potentially affecting desired plants nearby. This can cause unintentional damage to trees and shrubs, resulting in stress or even death to the plants that were not intended to be treated.

Additionally, understanding the root system extension is crucial because many trees and shrubs have extensive root networks that can reach beyond their immediate vicinity. Herbicides can be absorbed by roots that have penetrated into treated areas, leading to detrimental effects on the health of the plants. Therefore, when applying herbicides in such environments, careful attention must be paid to both drift prevention and the root systems of nearby vegetation to minimize harm.

In contrast, while root damage, chemical resistance, and herbicide effectiveness remain important considerations in pesticide application, they are secondary to the immediate risks posed by drift and the proximity of the plants' root systems. Managing drift and being aware of root system interactions directly affects the health of surrounding vegetation, making it the primary concern during the application.