Re: shredding burlap?
I am a cheap bastard and I wanted some long strands dyed the way I wanted them dyed, so I bought a couple bolts of burlap and dyed full width x 6' lengths with Rit dye in varying intensities of tans, browns, and greens (intensity is all predicated on how much dye you use and how long you let it sit in the hot water with the dye); then I hung them to dry out. Next I laid each section across a table and cut about an 1" off the end of the section of fabric (across the width of it) removing the 'seam' at the end so as to 'free it'. Next I took a sharp pointed tool (think small sharpened punch) so as to lift one horizontal thread and pull it free from all vertical threads. I pulled every horizontal thread free from every vertical thread.
Did it take a mega shit ton of time to do this? Yes. The only reasons I would say anyone should do it this way are:
A) You're a cheap bastard that places no value on your time
B) You want a variety of color tones that you are not seeing in the pre-dyed jute
C) You think using mainly strands plus a few intermittent strips, plus veg create more variety of depth and texture and thus look better than just clumpy strips of jute + veg
Good luck