Native to South Africa, Crassula Rupestris (also known by several common names such as Baby’s Necklace, Rosary plant, Kebab bush, Concertina plant, Stacking Crassula, Rosary Vine, Necklace Vine, and my favorite–High Voltage) are striking succulent plants similar to their popular distant cousin, Crassula Perforata (String of Buttons). Both of these plants have a lot of similarities in features and growth patterns that they can be mistaken for one or the other. Crassula Rupestris have small, tight leaves that are more pointy and star-shaped in appearance compared to Crassula Perforata. The leaves sprawl and stack on top of each other as they grow. The leaves appear to spiral around the stem, forming a beautiful intricate pattern. The leaves are pale green in color with crimson red edges. The color intensifies with increased sun exposure.

The plant grows straight up at first, then sprawls and appears to spill out of the pot as it matures. They can grow upto over 1 ft. (30cm) long. Another difference between Crassula Perforata and Crassula Rupestris is the flowers they produce. Crassula Rupetris produce clusters of flowers similar to Baby’s Breath in appearance. The shape of the clustered flowers are round, whereas Crassula Perforata’s blooms are more elongated and protrude outwards. The colors are in different shades of pink with some yellow. These plants are so striking to look at, especially when in bloom.

Crassula Rupestris 'High Voltage' in full sun with crimson red edges on the leaves

Looking at the crimson red edges and it makes sense why these plants are also called ‘High Voltage’. The gorgeous vibrant colors intensify with more sun exposure. 

Crassula Rupestris 'High Voltage' in full sun with crimson red edges on the leaves

Crassula Rupestris ‘High Voltage’ Care

 

Are They Indoor or Outdoor Plants?

Crassula Rupestris ‘High Voltage’ can be grown both indoors and outdoors. Whether indoors or outdoors, providing the right potting mix (a well draining one) along with proper lighting will give them the best chance at survival.

 

Indoor Lighting Requirements

It is best to provide as much light as possible if kept indoors. Typically speaking, they need approximately 4-6 hours of light per day to thrive. If your area does not receive adequate light or if you have poor indoor lighting, you may notice the plant stretching out or elongating. This process is called etiolation, where the plant literally seeks out more light and therefore stretches out. This process weakens the plant and produces brittle stems and poor growth. When your plant starts behaving this way, it is not receiving enough light. Move it to a brighter location. Choose an east facing window. A south or west facing window will also work.

For poor lighting conditions, or for areas that do not receive adequate sunlight indoors no matter where you place your plant, consider using a growlight. Growlights are a good investment to have especially if you have long, dark winters. Here are some of my growlight recommendations.

To read more about indoor lighting for succulents, check out my post on “Proper Lighting for Succulents Indoors” to get more helpful tips.

 

Outdoor Sunlight Requirements

Crassula Rupestris ‘Baby’s Necklace’ do best in areas that receive plenty of sunlight. They can tolerate partial sun to full sun, but need to be acclimated to full sun to prevent sun damage. I find Crassula Rupestris more tolerant to full sun than Crassula Perforata. I have mines growing happily in full sun, which brings out the intense crimson-red color on the edges.

Place in a bright sunny location outdoors. Before moving the plant outdoors or increasing the amount of sunlight it receives, it is better to acclimate the plant to help prevent sunburn or sun damage. Slowly increase the amount of sunlight it receives until it is fully acclimated to the sun. Keep in mind that even when the plant is already acclimated to full sun, it can still get sunburned under intense summer heat or during a heatwave.

Crassula Rupestris ‘High Voltage’ are hardy in USDA hardiness zones 9-11.

Sunshades are a real lifesaver for my plants during the intense summer heat here in Northern California where the temperatures can rise above 100℉ or 37.8℃. Here are some of my recommendations for sunshades and sun protection.

For further details and information on outdoor sunlight requirements, please visit my post “How Much Sunlight Do Succulents Need Outdoors?” to get some useful tidbits.

 

Frost Tolerance

Crassula Rupestris can tolerate mild frost and freezing temperatures as long as they are not for prolonged periods of time. If you live in USDA hardiness zones 9-11, you can get away with leaving the plant outdoors all year long. They can even be planted in ground. I am lucky to live in sunny California where winters are mild. I keep mines outdoors all year long, and they survive the freezing rain and frost we experience during winter because of all the sun we get during the day.

If you have extreme winter conditions in your area, the best way to grow these plants are in containers. That way you can bring them indoors during winter or when there is forecast of frost or snow. In case you can’t bring them in, there are ways to protect the plants from frost and freezing temperatures outdoors. Frost protection such as frost cloths and greenhouses can help them survive the cold winter. Here are some of my recommendations for frost protection.

For further details on this topic, visit my post on “Optimal Temperatures for Succulents to Survive and Thrive.”

Crassula Rupestris 'High Voltage' Plant in bloom with clusters of pink flowers
Crassula Rupestris 'High Voltage' Plant in bloom with clusters of pink flowers

Soil Requirements

Just like most succulent plants, Crassula Rupestris needs a well draining soil. A well draining soil is very important because these plants are susceptible to root rot. I have had great success with using a simple mixture of cactus potting mix combined with perlite for added drainage. I do not use exact measurements but eyeball it to about 2:1 solution of cactus mix and perlite. Using a sandy soil is also highly recommended. This can be achieved by mixing cactus mix or potting soil with coarse sand (about 2:1 ratio).

I get most of my materials from a local hardware store. You can also purchase them online if needed. Here are my some of my soil recommendations. To read more about soil for succulents, click on “Best Soil and Fertilizer for Succulents” to get more useful information.

Watering Requirements

Watering largely depends on the climate you live in. Although these plants are highly adapted to dry weather conditions, they do much better when given sufficient amounts of water. There really isn’t a set schedule or formula on when to water succulents. My watering schedule is dictated by the very dry climate I am in.

In the summer months, I water my Crassula Rupestris as often as every 7-10 days, sometimes more during a heatwave. I cut back on watering to about every 10-14 days when the weather cools down. During the winter season, I mostly rely on rainwater and hold back on watering altogether because this is when we get a lot of rain in my area. But if we don’t get any rain at all during winter then I water at least once a month or every 2-3 weeks, depending on how dry the soil gets.

In humid climates, you won’t need to water as much. And if you keep your plants indoors, you do not have to water as much especially if they are not receiving a lot of light. Too much water and not enough light is a recipe for disaster for these plants.

One good way to tell whether it’s time to water is to check the moisture of the soil. The top inch of the soil needs to feel dry before you can water again. If you are unsure how much and how often to water in the beginning, it’s always better to underwater and increase watering as needed. Pay attention to how your plant looks and you can adjust watering accordingly.

For further help with watering techniques, consider using tools like hygrometers or moisture meters to check for moisture in the soil and air. These tools are pretty affordable and can come in handy especially if you are unsure of when to water your plant next.  I have narrowed down the choices here on my resource page. Do visit the page if you need help in gauging your watering needs.

Useful Tip: Do not let water sit on the leaves of the plant. Water the base of the plant instead of from the top. The way the leaves of Crassula Rupetris are shaped, water can collect on the leaves and when they stay wet, rot starts setting in on the leaves.

Interested in finding out more about watering succulents? Visit my post “How And When To Water Succulents” where I go into details about this topic.

Crassula Rupestris 'High Voltage' Plant in bloom with clusters of pink flowers
Crassula Rupestris 'High Voltage' Plant in bloom with clusters of pink flowers

Propagating Crassula Rupestris

The easiest and quickest way to propagate these plants is through stem cuttings. They can be propagated from leaves, but I find the process more tedious and time consuming. I have had greater success using stem cuttings. If you want to try to give leaf propagation a try, make sure to use the entire leaf which goes around the stem, including the base to ensure success.

 

How To Propagate Crassula Rupestris:

  • Obtain a stem or leaf cutting and let it dry for a day or so. Since the stems are thin they shouldn’t take that long to dry. It is also a good idea to obtain cuttings from healthy looking plants, not dehydrated ones.
  • (Optional) Dip the cut end in rooting hormone. I usually skip this step but some people prefer using rooting hormones to speed up the process and also guarantee success.
  • Once the cut has healed and dried, stick the cuttings in a well draining potting mix or lay the leaf cuttings flat.
  • Keep away from direct sunlight. Water or mist the soil every few days.
  • After about two weeks or so, you will notice new roots growing.
  • After about four to six weeks, the stem cuttings should be fully rooted and you will soon notice new growth developing from the top or the sides of the stem. Leaf cuttings generally take longer as you would have to wait for a new plant to grow. Use more than one cuttings just in case some of them don’t make it.
  • Once the plant is rooted and more established, you can switch to regular watering instead of misting and cut back on the frequency of watering to once a week or less. Increase the amount of light it receives as the plant matures.

With just a few steps and a little bit of patience, you will have yourself a few baby Crassula Rupestris growing everywhere.

 

Common Problems with Growing Crassula Rupestris

 

Brown Leaves

The most common cause of brown leaves on Crassula Rupestris is sunburn. Although this plant can take full sun, any extreme weather conditions or extreme changes in weather such as a heatwave can cause sunburn or sun damage. This does not really internally hurt the plant as long as the problem is temporary. If you notice the plant constantly getting sunburned, move the plant to a shadier location or provide shade under taller plants, furniture, or sun shades.

It is a good idea to slowly acclimate the plant when moving to a sunnier spot to avoid shocking the plant or burning it.

Shriveled Leaves

The most common reason for shriveled leaves on Crassula Rupestris is underwatering. The leaves will look shriveled, wrinkly and dried up. When touched, the leaves will feel flat and thin. When this happens, it is a sign that the plant is running low on its water storage and it is time to water. Just give the plant a good drink of water and it should perk up immediately, usually within a day or so. When watering, it is better to water the plant thoroughly as opposed to little mistings here and there. Then leave it alone until it dries out before watering again.

Mushy Brown Leaves

The most common reason for mushy brown leaves on Crassula Rupestris is overwatering. The plant starts looking sick and the leaves will appear lighter or translucent. The leaves will also feel mushy. These are usually signs you are overwatering your plant. Simply cut back on watering and allow the plant to dry out and recover from too much water. Do not water until the plant has had a chance to dry out completely. If the soil is not drying out fast enough, consider switching to a fast draining one. These plants are susceptible to root rot when left in wet soil for too long.

Once you notice the plant turning brown or black, it usually means the plant is starting to rot. You can still save the plant by cutting off the rotten dead parts of the plant. Save anything that looks green and viable to propagate and repot.

Remember, it is easier to ‘fix’ an underwatered plant than an overwatered one so when in doubt, err on the side of caution when watering especially if you are not familiar with the plant.

 

How To Get Crassula Rupestris to Bloom

As if they are not pretty enough, they get even more beautiful once they bloom. Crassula Rupestris produces clusters of pink and yellow flowers that surround the plant and transform it to an amazing array of colors. Keep in mind that not all plants are ready to flower, and some may not bloom at all. A lot of it depends on environmental factors beyond our control.

Crassula Rupestris 'High Voltage' Plant in bloom with clusters of pink flowers
Crassula Rupestris 'High Voltage' Plant in bloom with clusters of pink flowers

Here are some tips on how to encourage Crassula Rupestris to bloom:

Plant Maturity

Make sure the plant is mature enough. When a plant blooms it means it is ready to reproduce. If the plant is too young, it is simply not ready to reproduce and therefore will not bloom. Give the plant some time, usually if the plant is over 3 years old and beyond, it is mature enough to bloom.

Plenty of Light

Make sure the plants are receiving adequate sunlight throughout the year and are kept in a bright location, even during colder winter months.

Proper Temperatures

To encourage flowering, provide proper temperatures. They need a distinct difference in night and day temperatures as well as summer and winter months. Succulents favor cooler outdoor nighttime temperatures of 50-55⁰F (10-13⁰C) or indoor night temperatures of at least 60-65⁰F(15-18⁰C). Especially when kept in a controlled environment, succulents prefer a marked difference between their night and day temperatures to mimic their natural habitat, with the cool night temperatures having an integral part in the plant’s growth cycle.

Overwintering

Overwintering is also important if you want to see your succulents bloom. This can be achieved by keeping them cool and relatively dry in the winter months, especially desert cacti.  Keep them cool during winter months with temperatures just above freezing, between 35-44⁰F (1.5-7⁰C). If kept indoors during winter, have them in a non-heated room if possible or keep the temperatures low to provide them the cold winter period that they need.

Feed or Fertilize

While fertilizing is not necessary, giving your plants the nutrients they need will help ensure proper growth and encourage blooms. It takes a lot of energy for plants to produce flowers, and feeding them extra nutrients will help supplement their needs during flowering season. The most common recommendation is to fertilize during the active growing season, or during spring and summer months. Fertilizers are better applied at a quarter or half strength, about every two weeks. Refrain from fertilizing towards the end of fall season and during winter months. A balanced blend of fertilizer diluted to half strength is suitable and commonly used. Fertilizer blends specially formulated for cacti and succulents are also suitable.

 

Toxicity to Cats, Dogs or Pets

There is not enough information regarding the toxicity of Crassula Rupestris to pets. The ASPCA does not list them as toxic to pets. Check out the ASPCA website for more information. If you suspect poisoning, contact your local veterinarian immediately or the ASPCA Animal Poison Control Center at 888-426-4435.

 

Crassula Rupestris is such a gorgeous looking plant and all-in-all trouble-free. If I don’t find myself admiring its beauty, I pretty much ignore the plant and it seems to thrive with neglect or very little attention.

Check out my other post on Crassula Perforata ‘String of Buttons’ to compare these two plants. They are very similar in appearance and care requirements.

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Crassula Rupestris 'High Voltagee' Plant in bloom with clusters of pink flowers
Crassula Rupestris 'Baby's Necklace' Plant in bloom with clusters of pink flowers