1. Bark Mulch. Cheap, soaks up wee, easy to pick up poo, natural, mfortable for dogs, improves soil. Needs to be topped up over time, can spread onto pavers. 2. Pebbles. Drains well, easy to clean with a hose, looks neat & tidy. Large pebbles make it harder to pick up poo, can be uncomfortable for dog feet. 3.