Cold weather is a common reason for Jasmine to turn brown, but lack of water and disease can also cause browning. Did the browning start from the bottom of the plant or the tips of the leaves? If the leaves turned brown during the winter I would suspect the weather is to blame. In that case you can cut the plant almost to the ground and see if new green growth sprouts later in the spring. Leaves that have turned brown will not green up again so you might as well cut them off. Good luck and Keep growing, Marianne Binetti