January 2012


This plant comes from Socotra which is an island belonging to the Republic of Yemen. It is one of a number of unusual caudiciform succulents that occur there. It can reach a height of 2 metres and looks very imposing. In the greenhouse, it should be kept warm and it will not lose all its leaves. You require two plants to produce seed. Normally, Dorstenias produce seed freely without having to be cross-pollinated, but Dorstenia gigas is one of the exceptions. Propagation by cuttings is very difficult, but there is a nursery in Holland that propagates this plant by means of tissue-culture.
They grow reasonably quickly in cultivation, especially if kept warm and given reasonable amounts of water. It will start to flower when it is about a metre tall which can take several years. It can be grown in a variety of soils, but do bear in mind that the colder the greenhouse, the more grit will have to be added to the compost to avoid rotting.

Dorstenia gigas

Dorstenia gigas leaves

Dorstenia gigas

Dorstenia gigas young plant

There are two variations of Dischidia nummularia; one a plain green one, the other with variegated leaves. The green form flowers a lot easier with small white flowers. Dischidias are very closely related to Hoyas, so much so, that a number of species cannot be told apart until they flower. Dischidia nummularia variegata is a good example; it was a few year before it flowered and I could work out what it was. And for one or two species of Dischidia, even when they flower, the experts cannot determine – or do not agree – whether they belong to the dischidias or to the hoyas.
Dischidia nummularia comes from South-East Asia and is an epiphyte, growing on the tree trunks. Because the flowers are small and often appear well above head height, they are difficult to spot. It likes plenty of light to grow well and if you are lucky you will get flowers, but it may take a while. It is an untidy grower and likes plenty of space. The plants can be grown in either a compost mixture or on a piece of bark or similar medium. Generally speaking, dischidias prefer a higher temperature than hoyas, but these two grow quite well in the same temperatures as hoyas. Both are very easy to propagate by cuttings and will, in summer, root in about six weeks.

 

Dischidia nummularia variegata GPS 10249

Dischidia nummularia variegata GPS 10249

Dischidia nummularia GPS 10245

Dischidia nummularia GPS 10245

This is a very easy species to grow, just as easy as Ceropegia woodii. It is a trailing variety which will sometimes climb; it will grow very long, but do not be tempted to cut it back or you will lose the flowers. The flowers will appears when the plant has reached a length of about 1.50 metre. The flowers are about 2cm long and do not stand out. The leaves are long and thin, hence the name linearis. If you grow a stem horizontally, for instance on a potting table, the nodes will send out roots if they touch the soil. This is an easy way of propagating the plant, which is useful as linearis seed is rarely produced.

It is a tuberous-rooted species and the tubers will form from cuttings, as is true of all tuberous-rooted ceropegias. It will grow in most soils and requires only a little bit of heat (5-10°C) in the winter. In the summer, it prefers to be grown in a shady place, but temperatures can be quite high without any problem.

Ceropegia linearis

Ceropegia linearis