Marsdenia oreophila (Cionura oreophila hort)
Marsdenia oreophila is a rare evergreen climber of the milkweed family, like the other milkweeds it has scented flowers (Waxy white) although to my nose this is both the strongest and sweetest scent of the group. Not fully hardy (min -5c to keep leaves) but worth trying on sunny sheltered walls or in the conservatory where its scent is even more strongly noticed.
is a native
of SW China, in Yunnan, where it apparently grows in hedges and scrub,
in May–August. Stems to 2m higher on a warm wall; leaves to 6cm
1cm across, in umbels of around 10. There is a good plant of this growing in the
open without wall protection at Tremenheere in Cornwall, and another at
Stonehouse cottage near Kiddrminster on one of the walls. For any
reasonable soil with ample water
summer, drier in winter.