Denzo or Denso tape is from any engineers merchants or plumber shop,
Normal industrial use is waterproof wrapping of say gas pipes etc.
Horrible gummy stuff to apply so use plastic or rubber gloves.
Do the binding around like insulation tape (overlap each run min 50%)
and then smooth it over with your gloved hands creating and impervious goo
The smoothing can be light rub over giving the warp and weft of the hessian
or hard press bringing more goo to the surface allowing a fine flat finish.
Generally it is a dark green which turns black with time and dirt.

One decision you'll have to make before hand is whether to grease the leaves
or not.

Dave Martin