Cut a 6-8 inch length of wood after the blooms have faded.
Leave the top two leaflets. Dip in Root Hormone Stimulat. (You can get this at the Wal-Marts garden department.)
Set the cuttings into damp soil mix.
Seal the pot in a plastic bag until new shoots appear...about 5 to 8 weeks.
I've started numerous plants this way.