Mesembs are highly succulent plants originating largely in southern Africa. Some genera are well known, such as Lithops, Conophytum and Pleiospilos. Others are not so well-known, and Cerochlamys gemina is a species from one of the many other fine genera available to cultivate!
There are few greenhouse flowers in January and February, but this is the time that C. gemina produces its numerous, gorgeous lilac blooms. The flowers are about 25mm in diameter while the leaves are roughly 30–40mm long, held in tufts on the end of short stems. It does not grow quickly, but in age will develop into a mat; you can see the stems start to scramble in the pictures. If the stem gets too long, it is easy to cut the end off in spring, then let the cutting dry for a week or two, and set it in soil (as recommended below) to root down. The plant can be grown nicely in an 8cm pot or a larger pan, if that is what you fancy!
It is easy to grow, but prefers a fairly dry compost. For all my mesembs, I use 75% horticultural potting grit with 25% loam-rich soil. I also try and grow my plants in small pots, partly so I do not molly-coddle them and partly so I can fit more into my small greenhouse!
Hailing from near Ladismith in South Africa, in habitat C. gemina receives limited rainfall throughout the year, with slightly more in spring and autumn. In the cloudy, damp UK, I water in spring and autumn. I always water till it flows out the drainage holes in the bottom of the pot, then wait for the pot to dry, wait a bit more and water again.
C. gemina grows readily from seed. I recommend sowing in spring onto fine soil which is 50% fine grit (about 1mm diameter) and 50% seed compost. I use seed compost since it is usually milled finer. I think they need light to germinate well, so I do not cover the seed. I press them into the surface and spray heavily so they get good contact with the soil. I use a propagator, so they stay moist for a couple of weeks after germination, after which I gradually open it up. I then keep them moist at the roots for 9–12 months, by which time they have become big enough to survive a 3-month drought!
Originally described as a species of Ruschia, this species was added to the genus Cerochlamys because of subtle features of the fruits, but you can still find C. gemina listed under the genus Ruschia in many places. Cerochlamys means ‘waxy sheath’, referencing the waxy leaf surface that most species possess.
The main pest I find is western flower thrips. It does not really cause many problems on Cerochlamys itself, but it migrates to nearby Lithops where it is bad news! I use SC Invigorator regularly through the watering season to keep these down.
David Lambie
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