I use the plastic deer fencing (sold at ant home depot/lowes). As long as the
big guy is not a digger, I'd recommend using that along the bottom gaps. it cuts
to any width (It is sold in 6 and 8 foot heights) I use tye wraps to secure it
and leave it long enough to cover with dirt, and grass. I also use it on my
deck, and it is great as a temporary indoor 'gate' using chairs to secure the
sides.