Lithops 101

Lithops spp. (Living Stones)

Lithops is a genus of succulent plants native to Southern Africa. "Lithos" means "stone" and "-ops" means "face" in Ancient Greek; therefore "Lithops" means "stone-like". The formation of the name from the Greek "ops" means that even a single plant is called a Lithops. This is a very good description of these plants, which avoid being eaten by blending in with surrounding rocks. They are also called ‘pebble plants’.

The genus Lithops is in the family of Aizoaceae, which also includes the various forms of plants known as "Ice Plants" and those called "Mimicry Plants". Lithops are commonly called Living Stones because of their remarkable resemblance to rocks on the ground. In a rock covered landscape, they are nearly indistinguishable from actual stones. In fact, the plant’s ability to blend in using its color and shape is the most startling adaptation of Living Stones. The leaves are not green as with many foliage plants, but various shades of cream, grey, brown, reddish browns, purplish browns, and grass-greens with a myriad of patterns such as darker windowed areas and designs, dots, red lines and areas known as "islands".

There are well over 300 types of Lithops. Several types differ in nearly all areas including texture, size and color. They may look similar, but are in fact very unique. No two Living Stone plants are going to look exactly alike. They are popular novelty house plants and many specialist succulent growers maintain collections.

Individual plants consist of one or more pairs of bulbous, nearly fused leaves opposite to each other and hardly any stem. The slit between the leaves contains the meristem and produces flowers and new leaves— leaves which are mostly buried below the surface of the soil. They have a characteristic top to the leaf which is a partially (or completely) translucent surface (or window) allowing light to enter the interior of the leaves for photosynthesis.

Lithops are extremely succulent bilobes (up to 90% water). A single body can be to 1.5" in diameter, and is split by a central "cleft", creating the "bi-lobed" body. Many species eventually form clusters, and in the native habitat, clusters gradually spread to from large colonies of Lithops that can span 6 feet in diameter. The rarer green forms occur naturally in grassy areas, while the browns, tans and other colors occur in quartz fields, providing an example of a phenomenon known as "mimicry" in which a plant, insect or animal can become almost completely camouflaged by its surroundings and is virtually undetectable. This ability to blend in helps Lithops avoid predators – The markings on the leaves disguise the plant in its surroundings from hungry animals that would otherwise feast on its tender, fleshy bodied leaves.

Climate: Lithops occur naturally across wide areas of Namibia and South Africa, as well as small bordering areas in Botswana and possibly Angola, from sea level to high mountains. Nearly a thousand individual populations are documented, each covering just a small area of dry grassland, veld, or bare rocky ground. Different Lithops species are preferentially found in particular environments, usually restricted to a particular type of rock. Lithops have not naturalized outside this region.

Rainfall in Lithops habitats ranges from approximately 700mm/year to near zero. Rainfall patterns range from exclusively summer rain to exclusively winter rain, with a few species relying almost entirely on dew formation for moisture. Temperatures are usually hot in summer and cool to cold in winter, but one species is found right at the coast with very moderate temperatures year round.

Lithops often survive many years of drought with nothing more than seasonal fogs. These plants have evolved a strategy that enables them to absorb and store moisture from these scant fogs. As our climate is much more humid than that of Africa, Lithops can absorb much of its required moisture from the air.

Growth Habit: Lithops tend to grow in the winter and rest in the summer, contrary to many other plants! During winter a new leaf pair, or occasionally more than one, grows inside the existing fused leaf pair. In spring the old leaf pair parts to reveal the new leaves and the old leaves will then dry up. The leaves may shrink and disappear below ground level during drought. Within their native habitat, plants almost never have more than one leaf pair per head, the environment is just too arid to support this. Yellow or white flowers emerge from the fissure between the leaves after the new leaf pair has fully matured, one per leaf pair. This is usually in autumn, but can be before the summer equinox in L. pseudotruncatella and after the winter equinox in L. optica. The flowers are often sweetly scented.

After the plant flowers, the plant will rest for a short time. Then from the middle again two new leaves will start to form. They will take all the moisture and nutrients from the old leaves. This is why it is important not to water/fertilize (it will disrupt the process). The old leaves will shrivel and die and the new ones will come in and replace the old ones. After that point in time it is safe to resume watering/fertilizing!

Lithops' fruit is a dry capsule that opens when it becomes wet; some seeds may be ejected by falling raindrops, and the capsule re-closes when it dries out. Capsules may also sometimes detach and be distributed intact, or may disintegrate after several years.

Summer Dormancy vs. Winter Growth: Normal treatment in mild temperate climates is to keep them completely dry during winter, watering only when the old leaves have dried up and been replaced by a new leaf pair. Watering continues through autumn when the plants flower and then stopped for winter. The best results are obtained with additional heat such as a greenhouse. In hotter climates, the plant will have a summer dormancy when they should be kept mostly dry, and they may require some water in winter. In tropical climates, Lithops can be grown primarily in winter with a long summer dormancy. In all conditions, Lithops will be most active and need most water during autumn and each species will flower at approximately the same time.

Soil Type: Lithops thrive best in a coarse, well-drained substrate. Any soil that retains too much water will cause the plants to burst their skins as they over-expand. Plants grown in strong light will develop hard strongly colored skins which are resistant to damage and rot, although persistent overwatering will still be fatal. Excessive heat will kill potted plants as they cannot cool themselves by transpiration and rely on staying buried in cool soil below the surface.

Lithops requires a porous soil; note that very excellent drainage can be attained by the addition of extra pumice or other coarse material. It is preferable that the soil does not contain much organic material, such as peat moss and that the plant is not fertilized with heavy nitrogen as this can cause an explosion of soft, flabby growth that can make the plant prone to bacterial rots. Another good mix would be 40% peat moss and 60% perlite to allow even faster drainage.

What pot should I use for my Living Stones? In my opinion, plastic or terracotta pots are best. Since Living Stones are a succulent, a terracotta pot will not only fit the succulent theme (sand, rocks, deserts, etc) but also might help the plant dry out a bit easier. Since terracotta is porous, water goes through it easily, helping the pot dry out as well as the plant – especially if it’s in a sunny location! You could also use a glazed pot if you desire. In design terms, a glass container would look striking and allow you to watch the plants’ roots grow and develop—a very cool idea, indeed! Just be sure the glass container has a drainage hole. Many glass containers do NOT normally have a drainage hole, so please be cautious!

Light: Lithops requires full to very bright sun (either direct or indirect). Shade will kill this plant! It can take full strength sun, but be mindful of sun burning the leaves (I know this from personal experience). If your plant is in full sun, be sure to water every week (instead of every two--see below).

A window facing West, South or East should do nicely. Too much light is not a problem for Living Stones. Too little light is! If the plant appears to be 'reaching' for the window or light source, it needs more light! Stretching will cause the Living Stones to lose their rock like appearance and grow taller. If this begins happening, simply find another place with more light.

In the wintertime during active growth, you may want to move Living Stones closer to a window – they need as much light as possible when producing new leaves. The rest of the year, they still need sufficient light, but even if they aren’t right next to a window, be sure they can get some bright sunlight. Where you place your plants really depends on your window access (a house may have several whereas an apartment or other place may have only one or two) and your available space for plants. If you’re already obsessed with plants, the chances are good your space may be limited! The good news is: Living Stones tend to be small kept singly or in clusters. Plants grow slowly and don’t need huge pots or containers. If your plant space is limited, Living Stones may be a plant for you!

Watering: Keep plants barely moist! Overwatering is the most common problem people have with Living Stones. Overwatering will result in the death of this plant 9 times out of 10. One Lithops expert once remarked in regard to watering Lithops: "When in doubt, don't". During the cold winter months, watering should be light and infrequent once again, until such as time as the days grow longer and the temperature begins to warm a bit.

Generally, Lithops will do best being watered about once every two or three weeks (when not in active growth or flowering). Tap water or distilled water is fine. Treat it as a cactus. The plant can take a 'misting' every other day if desired, but this is not required. Be sure not to overwater! It will take up all the water that is put in the pot, even if its too much!

This next part is very important!!  Keep in mind, watering requirements will change throughout the year depending on which season you are currently in!! Lithops is a very unique succulent with unique watering requirements. Since overwatering is the number one cause of death for Lithops, it’s imperative growers learn exactly when (and when not) to water. For this reason, keeping these plants alive takes a bit of time and skill!

Spring:
The plant is dormant now. Water only if the leaves appear wrinkled.

Summer:
During the hot summer months the plants will be dormant and watering should be light and infrequent, only enough should be given to prevent the plants from shriveling or appearing "wrinkled".

Fall:
After the hottest part of summer, as autumn approaches, the plant will use most of its stored energies to flower. The appearance of buds signals the start of another watering period. Plants should be watered enough during this time that the bodies remain turgid, or, in other words, do not become "wrinkled". Watering should be thorough, but less frequently than for other succulents.

After the flower dies off, ALL WATERING/FERTILIZING SHOULD BE STOPPED!!

Winter:
Water should be withheld as the new leaves begin to appear in the cleft during winter time. You must do this so that newly forming leaves are allowed to absorb the moisture from the old leaves, or the plant will be more prone to rot and the new plant formed will be smaller than before, rather than growing larger as it should. When it is apparent that the new leaves have absorbed the moisture from the old leaves ~ nothing but a dry husk will remain of the old leaves ~ that is the signal that it is time to begin watering normally again.

What happens if I overwater?
If you have consistently overwatered Living Stones, it will likely die, especially if planted in the wrong kind of soil (soil that retains lots of water, such as peat moss). If you’ve only overwatered once or twice, the plant will fill itself with water and ‘bulge’ out. Anymore water at this point can burst the leaves. Your best option is to withhold watering again until the leaves have once more reduced to normal size. Water thoroughly when soil is dry to the touch during the active growing periods. If the plant is shriveled during the non-growing periods, water a very little bit, just so the leaves perk up.

I repeat, if too much water is given at ANY time, the plant will swell and then split. If this happens, you cannot go back!! Take care when watering, and water sparingly. Take note of the seasons, and be confident in your Green Thumb!

Temperature: Living Stones will do fine in just about any temperature that it is given. Naturally found in the deserts of South Africa, the plant will do fine with hotter temperatures. Lithops are somewhat cold tolerant, but it is advisable to provide frost protection to prevent possible scarring. Colder temperatures are okay, but by no means ideal. Do not allow your plant to freeze. If this happens, the plant will die. Lithops prefers a wide spectrum of temperatures above 50 degrees, pushing into the 90-100 degree range (that being the absolute hottest the plant can handle). Ideally, you want your plant to thrive at a temperature around 65 to 75 degrees.

Flowering: Flowers appear from August to November, depending upon the species, and usually open in late afternoon, but open on multiple days. At this time, the plant is nearly obscured by flower heads to 1" in diameter that are composed of frilly, satiny yellow or white petals.

Living Stones will typically bloom in the fall. A blooming plant means it is at least 2 to 3 years old (juvenile plants cannot bloom since they need a ton of energy to do so). Only mature plants that are well cared for will bloom. Often times Living Stones only bloom in greenhouse environments or for professional growers. If your plant does bloom, it must like its location and current conditions! Daisy-like flowers of white or yellow last about a week and then die. Give the plant no water or fertilizer when it’s flowering, as this will interrupt the natural cycle (something you should avoid!)

Propagation: Propagation of Lithops is best done by seed or cuttings. Cuttings can only be used to produce new plants after a plant has naturally divided to form multiple heads, so most propagation is by seed. Lithops can readily be pollinated by hand, and seed will be ripe about 9 months later. Seed is easy to germinate, but the seedlings are small and vulnerable for the first year or two.

Fertilization: Fertilizer is a requirement that is of some debate with growers. To play it safe use a diluted amount of 20-20-20 plant food (about 1/4 strength) will be fine about once a month. Do not exceed this amount! After the plant flowers in late fall/early winter, no fertilizer should be applied to the plant until after the new growth comes in.

Reproduction: Living Stones will reproduce themselves by runner (a 'root' that will spread out). A new plant will come up (usually by the parent.)

Do’s and Dont’s:
Do not water or fertilize your plant when it is producing new leaves. This will disrupt the process which it needs to complete uninterrupted at this time.

Do not overwater your plant. It will swell and sometimes split. If this happens special chemicals will need to be applied so that bacteria does not enter the plant and cause it to die. If this is not done in time, the plant must be discarded and replaced.

Do give Lithops adequate fresh air and bright, indirect light. Full sun is excellent when and if the plant(s) are properly acclimated to the sunlight. If they have been grown in partial sun before being moved, move them steadily up to the window a little at a time over a period of about 2 weeks or so. By the end of 2 weeks, the plant will be fully acclimated to a full sun environment and will likely not sun burn!

In all, Lithops may seem like a daunting plant to successfully grow in the home, but with the proper education and patience, you can (and will) succeed. Pay attention closely to the watering requirements with this plant. I cannot over state this enough! If you have any questions about Lithops or other succulents, please email me at: espressomocha86@hotmail.com Please include pictures of the plant(s) in question if at all possible! Friend me on Facebook at: www.facebook.com/eirinn.cunningham

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