Nick Maclaren wrote:
How far apart can they be to still have the Clematis grow up the
structure?
A couple of metres. I would recommend using 20-30 cm squares; 10-15
is better for a screen, but you want light in winter.

Really?! A couple of metres?! Surely the clematis cannot reach from one
point to 2m away with nothing in between to climb on?

The wire we intend using is 10mm (o.4 inches) thick - is this too thick
for the tendrils to grab onto?
No, but that is rod, not wire! Surely 5 mm would be heavy enough, unless
you are trying to fortify the area.

) This conjured up an amazing trellis, with copper pipes for some
reason!

But perhaps he could put some wires in between the rods? You've
completely destroy his design !!