Are you located in a city or big town? If so, I understand your problem. But if you have some friends in the countryside you could use any type of long woody growth like hazel or willow. Have you thought about taking a look at what people are throwing away as 'garden waste' at the local recycling depot, as often there are masses of woody clippings there that might do.
We are very lucky living in the wild countryside so never being short of such materials!

Note that very soft woods, such as willow, will rot quickly, and are of use mainly for annual vines, such as peas or Thunbergias.

Thanks very much for your speedy replies - I'm in the city but I know where I can get some hazel from so will go and forage. Thank you