We use this product for spring kick off weed control.I researched for hours the best lawn product to keep the harder weeds away. Preen DOES NOT work on my mulch area weeds. The reviews said to lay each spring and fall for the first couple years and then once a year. I loosen the dirt to spread the granules about 1 inch below the surface where the weed seeds start and then a thick layer on top then water twice a year.Works great! Used it in late winter on several areas including large ground cover of monkey grass and another area with lilies. Huge difference in number of springtime weeds.I am getting acquainted with this product -- no problems, but as to effectiveness, since it is a pre-emergent product, only time will tellWas almost going to skip buying Snapshot this season... And then I saw all the weeds that we would have without it. After four seasons in a row of Snapshot, we have forgotten what it is like to pull weeds in our shrub beds. There is nothing that compares. The best!small granules, easy to spreadJust in time for Spring, Snapshot DG Pro eliminates the problem before it appears. Simply broadcast and wait for rain.worked awesome and so easy to use