>>64307they don't grow in Europe I think, that's why I don't know them
but you can even bind things with small tree saplings and lianas by twisting them for more flexibility
you can try beating them with a stick to soften them and check if it will still split
also weaving it into some kind of cordage (braids for instance) can improve it tremendously
found this:
http://www.youtube.com/watch?v=WeN14pr0A3E 