Field studies were conducted over 3 yr to evaluate imazapic, applied either alone or combined with other commonly used herbicides for peanut weed control. Imazapic applied early postemergence alone at 71 g/ha provided excellent weed control, maximum yields, and optimum economic returns. Variations of this treatment—such as half rate of imazapic applied alone, tank mixed with other herbicides, or supplemented with other herbicides—frequently had equivalent weed control and yield. However, these variations did not improve economic return. Greenhouse studies evaluated Florida beggarweed control as influenced by weed age, imazapic rate, and application type. The three application types were foliage only, soil only, and soil plus foliage. Control was independent of application type when Florida beggarweed seedlings were less than 20 d old. The soil-only application did not adequately control older seedlings. Foliage-only and foliage plus soil application were equally effective. Averaged across all other factors, imazapic was less effective controlling seedlings older than 20 d. At this age, seedlings produced trifoliate rather than unifoliate leaves. Absorption of ¹⁴C-imazapic by unifoliate and trifoliate leaves was equivalent. However, translocation was greater in unifoliate leaves. Reduced translocation by trifoliate foliage contributes to imazapic tolerance of older Florida beggarweed seedlings.