3 Times Stronger than Preen.
Active ingredient in Preen = 1.47%
Active ingredient in Treflan = 5%
Treflan is a versatile pre-emergent herbicide that can prevent the germination and growth of a wide variety of weeds in and around labeled tolerant plant material. Treflan prevents most annual grassy weeds. Treflan is also labeled for control of some broadleaf weeds. Treflan can be used for many sites in residential, commercial, and industrial landscapes. Weed prevention in and around ornamentals, flower gardens, and other mulched areas are typical landscape applications.