June 2011

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

Talinums are generally considered weeds; they produce seed very easily and in abundance and do not have to be cross-pollinated. This Talinum species, however, is an exception, because it does need to be cross-pollinated in order to produce seed. It is a caudex plant which comes from Guadaloupe, an island in the eastern Caribbean Sea.
This plant is rare in cultivation; it requires plenty of sun to produce a nice compact plant. Without flowers it could easily be mistaken for an Echiverea.

Talinum guadelupense

Talinum guadelupense

All Uncarinas originate from Madagascar. There are about 15 species and all species are in cultivation. There are three flower colours to be found: red, white and yellow. The latter is the most common. Only one species has a true caudex, Uncarina roeoesliana. It is also the easiest one to flower; it can already flowers when still small. The rarest is Uncarina leptocarpa, the only white-flowering species.
One reason that Uncarinas are not common in cultivation is that the seed does not germinate easily. Why this is, we do not know. Propagation by cuttings is not a substitute because they do not root easily either. In short: a difficult sort to propagate.
But, once you have managed to get yourself one, it is relatively easy to grow. It needs plenty of warmth and plenty of water in the growing season, but keep it dry in the winter. In the wild they can grow up to four metres, but do not expect that in your greenhouse or window sill.

Uncarina species