Q. I’d like information on living stone plants (lithops) and how to grow them.
Lithops, called living or flowering stones, are very curious plants which resemble stones or pebbles. Their native habitat is the deserts of southern Africa (South Africa, Botswana, and Namibia), where they grow among rocks. Their stone-like appearance protects them from being eaten by animals, as well as a great many plants being missed early on by humans. Lithops have become popular with growers of succulents and unusual plants.
Lithops belong to the Aizoaceae (ice plant) family, a large collection of 183 genera, almost all native to southern Africa. They are sometimes called “mesembs” (from the Greek word for noon), a term that reflects the plants' flowers opening at midday. The entire lithops plant consists of two leaves and a root system. The two succulent leaves are almost completely fused together, separated by a fissure or slit at the top of the plant.
Lithops leaf tops are translucent or contain windows allowing sunlight into the interior of the plant. This interior light enables photosynthesis deep inside the plant, sparing the leaf surface the desert's desiccating heat and light.
Each spring a new pair of leaves appears; the new leaves gradually absorb the old ones. After new leaves have fully formed in autumn, a single flower appears. Flowers usually open at noon and close by evening. Sweetly scented in some species, the flowers are star-shaped and primarily white or yellow, blushed with a pink tinge on the petals tips when closed.
Because they are small and thrive in low humidity, lithops make ideal house plants. However, it is important to mimic as much as possible the growing conditions in the wild. These plants need at least 4-5 hours of direct sunlight a day. Southern exposure is good, although shading especially in summer may be necessary during the afternoon. Watering is also important--lithops have a yearly cycle of growth which should be followed closely. In spring, water lightly, and let the soil dry out between watering. In summer continue watering sparingly. When watering give just enough to make the potting mixture barely moist, and letting the top two-thirds of the mixture dry out between waterings. Water in the morning, and use room temperature water, or use rain water. After flowering lithops needs little or no watering in winter.
Use a quick-draining soil mix. You can use a succulent or cactus mix to which extra sand (2-1 mix-to-sand ratio) has been added. To accommodate the plant's tap root, pots should be 3-6 inches deep. A top layer of coarse sand or grit can be added so that only the tops of the plants are exposed.
The Llifle Encyclopedia of Succulents lists lithops species and photographs of many of them.
Living Stones Nursery specializes in lithops and other succulents.
For tips on a variety of gardening topics, see our Plant Information Guides.
- Courtesy of NYBG Plant Information Service