Recently, a local lady kindly donated a kiwi tree to us. It hasn't been trained to a t-bar trellis, is in a large pot and seems totally out of control! As we've had other priorities ie turning a bit of field in to a workable and rabbit free plot, we've just put it in the greenhouse and left it (watering regularly). I feel sad when I see it as it looks neglected but it's also taking up a lot of space and getting tangled!

Getting to my question...can it been pruned right back and trained up a t-bar trellis or will heavily pruning it ultimately kill it?
Any kiwi advise will be gratefully received! Thank you
