Lithops is a genus comprised of about 40 species of colorful, stone like plants in the Aizoaceae family. These unique plants are native to the rocky deserts of southern Africa, specifically, Botswana, Namibia, South Africa, and southern Angola. Their rock-like appearance has earned them the common names of "Living Stones" and "Pebble Plants" but has also protected them from herbivores. Most of the plant is typically buried beneath the soil, with only the top portions of the leaves visible. These extra fleshy leaves may appear as thought they are opaque, but if they were to be cut in half, it becomes clear that the inside of the leaves its, well, clear! The intricate patterning on the top of the leaves not only serves as part of its camouflage, but also has windows. These windows allow light to reach all the way through the leaves and enable photosynthesis. While they are absolutely sought after by many succulent collectors, they are often a victim of ignorance. They are easy to care for when you know their requirements, but not easy to get the hang of if you are trying to figure it out on your own. That is where this article comes in! Below you will find everything you need to know about living stone care and some common mistakes that are made.

Light

      Like most succulents, lithops need bright light. Under a grow light or in a southern facing window with no outdoor obstructions is best. They do not do well in medium light and will stretch, or etiolate, towards the light. Without the proper amount of light, they will slowly decline and eventually die. I don't always recommend growing living stones outside because it is hard to shelter them from rain while still giving them the light they need. Watering living stones can be strange. Let's take a look at how to properly water these strange plants...

Water

     Lithops have several obvious stages of growth that tend to go with the seasons, but when grown in greenhouse conditions, they don't always line up. So even though the following paragraph is going to talk about living stones seasonally- remember to listen to the plant. Sometimes they can go a little out of whack and no longer grow in the seasons they should be growing in. Over time, this should correct itself.

     Lithops are most commonly sold in the summer, so let's start there. They should be dormant in the summer, meaning they are growing very little or not at all. At this stage of growth, they need very little to no water. Be sure to listen to your plant during this time when deciding whether or not to water. If the stones are firm and juicy, don't even think about picking up the watering can! If they are squishy and wrinkly, it is safe to give them a small drink. They will not need deep watering in summer. In fall, the plants will begin growing again, maybe even blooming. At this time, it is safe to water deeply. Be sure to allow the soil to dry out completely between watering. Once you notice the leaves begin to split and a new pair of leaves coming through the plants, stop watering until the old leaves have dried up completely. During this time, the living stones need no water at all. In fact, watering in this phase can kill them. In spring, after the old leaves have shriveled and died, now it is safe to water again. Back off on the watering in summer and repeat the cycle. It is imperative to allow the soil to dry completely before you water again. If you don't, then they can either die from root rot or begin making a new pair of leaves at the wrong time of year. 

Soil

     When it comes to living stones, the chunkier and faster draining the soil, the better. Your soil mix will determine how frequently you water. Commercially available succulent mixes are okay, but it is important to be mindful when using them, as they can hold on to a lot of water easily. Amending these mixes by adding more perlite or pumice will help to drain quickly. What is most recommended is living stone growing medium. These will almost look like fine gravel more so than the commercial soil they often come in. This may seem like they could never grow in this substrate, but think back to where they come from. Rocky deserts often look like they themselves are made of fine gravel!

Common Problems

     Lithops are admittedly not the easiest succulent to care for, despite being fairly disease resistant. Most problems that living stones experience are care related, with a few pests sprinkled in here and there.

Root Rot

     Prevention is the best cure for root rot, as often it is fatal for living stones. This is caused by an excess of water and/or poor drainage, meaning the soil is staying too wet for too long. Terra cotta pots, gravelly lithops soil, and diligent watering is the best way to prevent root rot. It can quickly affect the tap root and kill the plant. Often, it isn't spotted until the base of the leaves have gone squishy. This is too late to save the plant. If caught sooner, be sure to take the plant out of the soil to allow the roots to dry as much as possible. They are not very extensive compared to other plants, so don't be alarmed when you don't find many. Allow the plant to dry, trim off any unhealthy roots, then repot in well draining soil.

Plant Stretching or Getting Tall Quickly

     This is called etiolation. This happens when the plants are not getting enough light. This can also be fatal for succulents, but especially lithops. The more light they have, the quicker they can dry out, meaning improved health of the plants overall. While the plants will not shrink back down to their proper height when they begin to receive proper lighting, the next set of leaves will return to their proper, stout height.

Spider Mites

    Spider mites are tiny, spin webs, and feed on the sap of many houseplants. Often, you will find their webs or see the damage they cause before you see the spider mites themselves. Washing the leaves and increasing humidity will help to decrease and eliminate the population. Insecticidal soap and systemic pesticides may also be needed if the infestation is severe. For more information about treatment and identification, please reference the article titled Spider Mites and How to Deal With Them.

Mealybugs

     Mealybugs are a white, sap-sucking insect that produces honeydew that can lead to sooty mildew. They often hide on the underside of leaves and in tight crevices of new growth. They are easily treated with pesticides, an alcohol mixture, or beneficial insects. For more information on how to identify and treat mealybugs, check out the blog post titled Mealybugs and How to Deal with Them.

Wrinkly Leaves

     Wrinkles can mean a few different things. The direction of the wrinkles can help identify the issue. Horizontal wrinkles on the top of the living stones indicate thirsty plants! This is most likely to happen in fall when they begin to flower and come out of dormancy, but not split quite yet.

     Vertical wrinkles can be an early indicator of overwatering. Follow the same procedures as listed above for root rot.

     Wrinkles can also just be a part of their natural growth cycle! If you have been following the rest of the care instructions and the plant isn't showing other signs of distress, it may just be getting ready to split. Remember not to water your living stones when they are in the process of splitting and the old leaves are shriveling.

 

     Lithops can be challenging, but they are a wonderfully rewarding plant once you get the hang of them! There are so many species in cultivation, your collection could easily grow into something extraordinary! The most important part of the process is to be sure they are not getting too much water and are getting plenty of light. As always, if you have any questions or concerns, please feel free to reach out to cedarbridgebotanicals@gmail.com and I will be able to help!