It will cling to the wire and the rest of possible support, including the rack frame. From my experience with clems, they usually looking for vertical support and grow vertically much faster, when it is found. You can cut those shoots growing in the wrong direction. BTW, what is the size of your rack? By looking at the picture I would say it is quite small for Jackmanii. When established it can grow shoots of 3-4 m long in one season. It will swallow the rack in no time.
