Cliff from Paulden, Arizona writes
Prodiamine 65 WDG (Generic Barricade) is a pre-emergent herbicide that typically lasts for 2-5 months in the soil, depending on the rate applied and how much rainfall the area receives. Pre emergents work best when soil temps are close to 70 degrees in the fall and 55 degrees in the spring. If you are using a pre-emergent like this in an area with gravel or rocks, then it is important to use a higher volume of water when you are applying the product and immediately after the application so that the active ingredient is carried into the soil and does not just get absorbed on the rocks as it's sprayed. This product is safe for pets when used as directed and after the application area is completely dry. To kill actively growing weeds and prevent weeds from germinating Hi Yield Extended Control is labeled for areas such as gravel, driveways, sidewalks, walkways, patios, etc and will provide weed control for 3-6 months. Hi Yield 365 will kill and prevent weeds for up to 1 year (some weeds may require a second application). Please keep in mind that thick ground covering will make any application of a pre-emergent difficult, so if you have heavy cover, then you may consider removing the rock and adding an additional barrier such as weed fabric before replacing the rock.
Answer last updated on: 08/22/2021
