Caren White is a Master Gardener and instructor at Home Gardeners School. She has been associated with Rutgers Gardens for over a decade.
I have to admit that the first time that I was introduced to lithops, I wasn’t terribly impressed. They didn’t look like much. But the more I learned about them and their unique adaptations to their environment, the more interesting they became to me.
What are Lithops?
Lithops (Lithops spp.) is a genus of plants that are native to the arid regions of Namibia and South Africa. They have developed specific forms that allow them to survive in the harsh climate of those regions. They were "discovered" by Europeans in 1811. The plants’ colors match each tiny habitat so well that new species are still being discovered today because they are so difficult to spot.
Lithops have surprisingly large root systems for their size. The large root systems enable them to gather water in the extremely arid climates in which they live. They have no stems. Instead, their roots attach directly to their leaves.
The plants have only two leaves which are mostly underground. The structure that you see above ground is actually an epidermal window. An epidermal window is a translucent structure that allows sunlight in. Lithops need this structure since most of the leaves are underground so sunlight cannot reach them.
The two leaves are partially fused together with a clear division between them. The division is called the meristem. It is where the flowers and replacement leaves grow. Lithops grow new leaves every year, usually in the winter. The two new leaves grow in the meristem. In the spring, the meristem opens revealing the new leaves. The old leaves then dry up and die.
No matter the species, all lithops have daisy like flowers. The flowers can be white or yellow, depending on the species. The flowers usually appear in the fall. They are only open from noon until early evening. Pollination is usually done by bumblebee like insects and possibly also moths in the evening hours.
If pollinated, the flowers are followed by seeds that form in a pod known as a fruiting capsule. The capsule only opens when it rains, which is very seldom in their natural environment. The falling drops of rain hit the seeds causing them to splash out of the capsule, landing anywhere from an inch to a few feet away from the parent plant. After the rain, the capsule dries out and closes. Any seeds that were not distributed by the rainfall, remain inside the capsule until the next time that it rains and the capsule opens.
How to Grow Lithops
Lithops are hardy in zones 9 – 11. Most gardeners grow them as houseplants. They grow best in full sun but will survive on a minimum of 5 hours of sunlight each day. When grown indoors, a southern or eastern exposure window is preferred.
Use a potting soil that is specifically formulated for growing cacti. Lithops need very well-drained soil or they will rot. They also need a much larger pot than you might think. They have large root systems for their small size. Use a pot that is 3 – 5 inches deep.
In nature, lithops grow right at ground level. This is an adaptation to severe drought. When there has been no rainfall for longer than usual, these plants will shrivel up and shrink below the surface of the soil. When the rains return, so do the plants, plumping up and pushing back to surface level. When grown in a pot, plant your lithop slightly above the surface of the soil. You will be keeping it watered enough so that it will not need to shrivel up and shrink underground.
Watering will be the key to your success (or failure!) When you water, drench the pot and then allow the soil to dry out completely, usually about 2 weeks before watering again. As tempting as it may be to water more often, too much water will cause the plants to burst. It is better to err on the side of too dry than too wet.
Watering should be done on a strict schedule during the year that mimics the rainfall pattern in their native environment. Do not water during the summer when the plants are dormant. If they start to shrivel up, give them just enough water to plump them up and then stop. You can resume watering in the fall when the plants begin to flower. It will be easy to tell when the plants are about to flower. The meristem will start to open to allow the flower to grow. Stop watering during the winter when the plants are dormant again. During this time, the old pair of leaves that was replaced the previous spring will also dry out and fall off while a new pair is forming. Once the meristem starts to open again in the spring to allow a new pair of leaves to grow, you can start watering again.
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Lithops do not require any fertilizer.
How to Divide Lithops
Sometimes when the lithops form a new pair of leaves, it forms two new pairs of leaves. This is your chance to divide your plant if you wish. Gently dig up your plant. Carefully cut between the pairs of leaves and their respective roots. Then replant the two new plants immediately.
You don’t have to divide your plant if it grows an extra pair of leaves. It will be fine with the extra leaves.
How to Grow Lithops From Seed
Lithops grown outside of their native areas will not be pollinated because the insects that pollinate them in the wild are not present in other areas of the world. You can get around this by hand pollinating your plants yourself using an artist’s brush. Once the seed capsule forms, you can wet it, causing it to open and then harvest the seeds inside.
Surface sow the seeds in a pot filled with moist cactus potting soil mixed with perlite for extra drainage. Do not cover the seeds. They need sunlight to germinate. Mist the soil to keep it moist. You can even cover the pot with plastic wrap to help keep the soil moist.
Place the pot in a sunny window. The seeds will germinate best if kept warm, between 65⁰F and 80⁰F. Use a heat mat if necessary. The seeds will germinate any time between 2 weeks and 3 months. The seedlings will grow very slowly. It will be about a year before the seedlings are large enough to handle and repot into their own pots. Seedlings don’t reach maturity and bloom until they are two to three years old.
© 2020 Caren White
Caren White (author) on July 05, 2020:
You're welcome! Glad you enjoyed learning about them.
Danny from India on July 04, 2020:
Never heard about them, thanks for writing about it.
Caren White (author) on July 03, 2020:
You're welcome! So glad you discovered something new.
Heidi Thorne from Chicago Area on July 03, 2020:
Those are so cool! I never knew about them. Thanks for sharing!