Personally, I'd probably form it and dry it over two stacked styrofoam dummies, with paper towels holding the "branches" separate and away from the cake. It won't take long for it to dry, but I'd probably do it several hours ahead of time. Once it's attached, I'd add my flowers. I can't see it really clear, but that's what I'd do from what little I could see. Good luck.
There is a packaging, paper covered wire that the people in the UK use. We don't get it in South Africa but I'm dying to get hold of it. Alan Dunn uses it and look at 'stickytoffeepudding' pictures - hope I am spelling it correctly- it is so beautiful and makes a big difference to arrangements. Maybe you would be able to get hold of something similar. I would then just stick the arrangement with melted chocolate.