I've become very disillusioned with any trellis made of wood, as it's only a matter of time before the wood rots and the whole thing comes tumbling down. And, needless to say, trying to replace trellis when it's got plants growing up it is deeply frustrating if not impossible, as is trying to treat the wood. That's why I've started making my own trellis from 6mm solid stainless round bar. Should be good enough for my lifetime, after which it's someone else's problem.
The clematis we are supporting are those that are pruned heavily each spring and then grow back up the trellis so firstly they never get too heavy and secondly the trellis gets cleared and a chance to repair/re-secure it every year if need be.
I've become very disillusioned with any trellis made of wood, as it's only a matter of time before the wood rots and the whole thing comes tumbling down. And, needless to say, trying to replace trellis when it's got plants growing up it is deeply frustrating if not impossible, as is trying to treat the wood. That's why I've started making my own trellis from 6mm solid stainless round bar. Should be good enough for my lifetime, after which it's someone else's problem.