In the latest Asklepios, number 110, there was a very interesting article about Periploca graeca, a vigorous climber. This plant is one I have owned for many years and it grows extremely well outside here in the Netherlands, taking all that the weather can throw at it. It has survived temperatures down to -10°C.
My plant was removed from our garden at home and replanted at the nursery. Some root fragments must have been left behind, because there is now a smaller plant growing on the original spot which suggests that this species can be propagated by root cuttings. But I prefer to take stem cuttings which root fairly easily.
The plant flowers extremely well, producing hundreds of flowers every year, but no seed at all. It could be that I need a second clone of this plant or that the insect pollinator is not present in The Netherlands. The plant is available from specialist nurseries and can be added to the few species of asclepiads that can be grown outside in all weather conditions.
Link to the Asclepiad Society

Periploca graeca