October 2012


A good plant for cactus collectors, because in the winter it can take low temperatures (even a bit of frost) if kept dry. It comes from the Eastern Cape in South Africa and the tuber can grow to a height of 25-30 cm. The branches that grow on top of the tuber can, if they get too large, be cut back. The flowers develop all over the branches, so you do not lose them if you cut the top bits of the branches off. The flowers are similar in shape to those of Adenium obesum, but smaller. The pollinator is probably a moth as the depth of the flower excludes other pollinating insects. When pollinated successfully, twin seed horns will appear which grow to a length of about 5 cm, containing up to 30-40 seeds. The seed has a parachute on the end enabling it to be carried away to a new area to grow. You can tell the difference between an Adenium seed and a Pachypodium seed, because the latter has just one parachute, while Adeniums have two. It is important to remember that the seed from both these species must be sown fairly quickly after collection, because they have a short ‘shelf-life’. It can be kept for a maximum of one year, but the germination will only be about 10%, if you’re lucky. The fresher the seed, the better the germination, possibly up to 100% if sown the first few days after collection.
Pachypodium bispinosum is virtually identical to Pachypodium succulentum when not in flower. To tell them apart, you need to see the flowers; the ones from the succulentum are flatter. In the wild, their localities overlap a little bit, but there is hardly any cross-pollination, probably because the pollination needs different insects.

Pachypodium bispinosum caudex

Pachypodium bispinosum caudex


Pachypodium bispinosum flower

Pachypodium bispinosum flower

This unusual plant is a climbing species of the Acanthaceae family. You are probably more familiar with its cousin, Black-eyed Susan, Thunbergia alata. The mysorensis is a tropical species that comes from southern India where it is used as hedging. It can grow very large, 10-15 metres is quite normal. The plant is very striking with its red and yellow slipper-like flowers which are about 5cm in length. They hang from long pendants with up to ten flowers. The individual flower can last up to a week.
The species is occasionally seen in cultivation and requires a reasonable amount of room. It is propagated by seed and by cuttings. Cuttings need a high temperature to root, ±22-25°C and a high humidity. I have never had seed on my plant, so I do not know what conditions it needs to germinate, but as it is a tropical species, a high temperature is likely. Most cuttings will root in about a month, but some take longer. If possible, plant it out in the greenhouse or conservatory, rather than keeping it in a pot, as it will do much better then. I grow it in a shaded greenhouse, but whether it needs more sun to flower, I do not know yet.

Thunbergia mysorensis

Thunbergia mysorensis