How to Propagate rex begonia vine?
Propagate by semi-ripe cuttings

rex begonia vine · Cissus discolor
Grow in loam-based potting compost in bright, indirect light. Water freely during the growing season and apply a high-nitrogen fertiliser monthly; water moderately in winter. Provide trellis or obelisk if you want the vine to climb. See houseplant cultivation
Propagate by semi-ripe cuttings