EXCLUSIVE Garden Highlights Medium Riverstone 15 litre SKU: 342742 MODEL: GHRSM15 Error. try again later You've successfully joined the club $ 11 .98 each Available on orders $50 to $1500.More info × Mitre 10 MAvailable at Mitre 10 MEGA stores. Variants Garden Highlights riverstone is a smooth, grey river pebble that can be used as an alternative to bark for ground cover on gardens. Excellent in water features and as a pot topper. Features and benefits A clean, washed grade. Maintenance-free ground cover. Long-lasting and hard-wearing.