NO GROW is not a Weed killer, but a Weed Inhibitor, all original Weeds must be removed|Block Paving is natural colour sand colour with Stone Dust is grey & Polymeric dark|Suitable for Patios, Driveways and general Landscaping|Polymeric had been discussed as the demand for a block paving product that hardens, as grown considerably|A flexible joint filling sand when moistened then activates a binding agent to harden