Hexazinone (Velpar) is typically applied as a foliar treatment in which seasons, and is best for sprouts under what height; it can leach and persist for years?

• A. Early spring, late fall, or winter; sprouts less than 18 inches
• B. Summer; sprouts under 6 inches
• C. Spring only; sprouts over 24 inches
• D. Fall only; sprouts over 18 inches

Answer: (A)

Hexazinone is a systemic foliar herbicide used in forestry, and its effectiveness hinges on both when the target sprouts can absorb it and how the chemical behaves in the environment. When applied as a foliar spray, it is best taken up by small, actively growing sprouts, so applying during times when new growth is accessible and manageable—early spring, late fall, or winter—lets the foliage absorb the chemical efficiently. Sprouts under about 18 inches tall have the highest surface area-to-mass ratio and are most easily translocated by the plant to suppress regrowth, making this size threshold ideal for control with a foliar treatment. Keep in mind that hexazinone is relatively mobile in soil and can leach with water and persist for years, so applications must be planned with caution to protect water resources and non-target vegetation, following label requirements and site constraints.