How do you choose trellis and obelisk size for climbers?
Rose newbie here, with 3 David Austin generous gardener roses to plant. I'd like to build a freestanding trellis and obelisk to set the roses in an open sunny spot between my yard and my neighbors. I was originally thinking they could be freestanding bushes as I read that as a bush they are 4' wide x6' tall, but after more research it seems they are better suited to climbing. I see that the canes can grow 15' long, but I can't find any calculation to figure appropriate spacing and trellis sizes. Would a 5' (aboveground) x 7 or 8' wide trellis be too small for 2 bushes (with one planted at each end, and a 7' tall (aboveground) obelisk for the other? Or would it be better to plant 2 bushes on the obelisk, and a narrower trellis (4 or 5' wide x 5' tall) with 1 bush planted on center ?