Absorbed by leaves, roots and stems directly from the water. Works by inhibiting the weeds ability to produce carotene. Without this ability, chlorophyll is rapidly degraded by sunlight and the weeds die. 7 to 10 days after the initial application you will see bleaching at the growing tips of the weed. Full results may take 30 to 90 days. Results occur slowly - treat early in the season for an entire weed free summer.