Hessian sack - potato sack or similar (City Centre NR1)

I need to move a small tree, so I need a sack to contain the rootball. Has to be hessian or similar as I want to keep it in a large plastic tray with some water for a few days, so a plastic bag is unsuitable. Near Norwich city centre best - I live near NCFC stadium and don't want to travel far. Thank you !