River pebbles are riverbed stones that vary in size this product in particular has a max of 20 mm in diameter. River Pebbles have a range of colour but they are mainly brown and grey which brings a really nature look to any garden. Like Mulches they provide coverage to retain water and stop weeds from growing but they do not break down. These pebbles are great for in between pavers and footpaths, being very smooth and mostly even they can be easily stepped on.