Euphorbia lactea ‘Cristata’ has an interesting history, and many love to keep it as a houseplant. It is also known as the Coral Cactus plant due to its appearance.
It’s actually a mutated Euphorbia lactea plant that produces ruffled, waved leaves instead of triangular crests like its predecessor.
With its coral fan crown and its cactus-like body, it may look like a high-maintenance plant, but it is very low-maintenance and a good beginner plant.
In this post, you’ll learn how to care for an Euphorbia lactea Cristata plant.
Table of Contents
What is a Coral Cactus (Euphorbia Lactea Chistata)?
The Coral Cactus plant is a succulent that is a part of the Spurge family and is commonly known as mottled spurge.
Botanically known as the Euphorbia lactea ‘Cristata’, it is also commonly referred to as the Coral Cactus, Candelabra Plant, Crested Candelabra Plant, Crested Elkhorn, and Crested Euphorbia.
Thanks to its spikes, it is often confused with a cactus plant. However, it is not a cactus at all. In fact, it’s an entirely different genus of plant. But, it is a succulent plant.
Coral Cactus Mutation Hybrid
This false cactus is an unusual succulent because it is a mutated succulent. The unmutated parent plant is the Euphorbia lactea, which grows as a small shrub with spiky triangular points on its branches.
However, the Coral cactus mutation transforms these triangular points into large, crested, wave-like paddle leaves.
Botanists have attempted to recreate this mutation, but have been unsuccessful, whereas this mutation occurs naturally in the wild.
Because the stem of the Coral cactus grows so slowly, botanists and plant producers will usually just graft the mutated Euphorbia lactea onto the rootstock of another Euphorbia plant.
Usually, they will use a Euphorbia neriifolia due to its strong stem.
Coral Cactus or Crested Elkhorn?
The name Crested Elkhorn is given to this plant because of its ruffled, antler-like appearance.
However, because it is mostly known for its coral-like appearance, the name “Coral Cactus” is more apt as the leaves really look like coral reefs from the ocean.
Depending on how much sun exposure it gets, these coral-like leaves can come in many colors like green, red, blue-ish gray, silver, and purple.
It rarely flowers, but when it does the plant can produce pink or purple flowers.
Where Does Crested Euphorbia Lactea Cristata Grow?
Where can you typically find this growing, indoors or outdoors?
This plant is not cold-hardy and requires full sun to partial shade. Because of this, many growers will keep it indoors year-round, or they’ll keep it in a pot on the patio, and then when it gets cold outside, it is easy to move it indoors.
In warmer climates, the crested euphorbia lactea can actually grow as a hedge.
Size & Growth
Cristata is a very slow-growing succulent, hence why it is usually grafted onto healthy rootstock or another Euphorbia plant.
In fact, if left alone this succulent grows so slowly that it could take 5 to 10 years before reaching maturity.
If planted in a pot, it will typically reach heights of 3 feet tall and grow to 2 feet wide. Planted in tropical climates outdoors, it will grow as a hedge.
Toxic latex sap
The crested euphorbia can produce an incredibly toxic, thick, milky sap that is harmful to humans and animals.
When ingested, nausea and vomiting may occur. It can cause skin irritation, so wear gloves. Consider wearing eyeglasses to minimize the risk of the sap touching your eyes.
If it gets in your eyes, temporary blindness could occur. Always wash your hands after handling your Coral Cactus, even if you wear gloves. With these safety precautions, you should be fine.
Coral Cactus Plant Care
Crested Euphorbia plants are very slow-growing plants, but they are low-maintenance. Many love them as beginner plants for this reason.
They have similar needs compared to other succulent plants, such as low watering and indirect light.
Watering
Because it is a succulent plant, you do not need to water your Coral Cactus often.
Water your plant every one or two weeks in its growing period, spring and summer, when the soil feels dry about an inch down.
In autumn and winter, they do not need watering as often. Water them once a month in the cooler months.
If you over-water a Coral Cactus, it can develop root rot, but it does not tolerate being under-watered the way a cactus does.
Temperature and Humidity
Crested euphorbia grows best at 60 to 85 degrees Fahrenheit-making it a great indoor houseplant.
To be grown outdoors, Euphorbia lactea Cristata prefers full or partial shade conditions and grows best in USDA Hardiness Zones 10b, 10a, 11b, and 11a or other temperate regions.
The lowest temperature it can withstand is 40 degrees Fahrenheit. If you want to grow this plant in cool regions, treat your Crested euphorbia as a potted plant.
Bring them indoors during the winter or when temperatures begin to drop.
Light
Coral Cactus plants thrive in direct sunshine. It requires at least 2 hours of sunlight per day and can tolerate full sun for longer than 6 hours per day.
Keep your plant near a window that gets a few hours of sunlight per day if you keep it indoors as a houseplant.
If you have it outside and live in a hot area, make sure it has some partial shade. If it is in direct sunlight for too long, it can burn.
Soil
Crested euphorbia needs well-draining soil. Using potting soil could lead to root rot. Cactus potting soil will meet your plant’s needs.
If the soil and pot both drain well, your plant will be less susceptible to root rot. These plants are not particularly pH-sensitive and will do well in either alkaline or acidic soil.
The best option to use is to buy cactus potting soil that is specifically designed for succulents or cacti. This particular cactus soil is what we use.
Fertilizer
Although Crested euphorbia succulents do not typically need fertilizers, during the growing season, which is the spring and summer, you can fertilize your plant with a 10-10-10 fertilizer diluted to ¼ strength.
What are the three numbers listed on the front of fertilizer packaging? The three different numbers refer to the amounts of NPK (nitrogen, phosphorus, and potassium). In a 10-10-10 mix, each nutrient makes up 10% of the fertilizer. So, three is 10% of nitrogen, 10% of phosphorus, and 10% of potassium.
Pruning
Crested euphorbia typically does not need pruning unless the leaves are rotting. If you want to trim your plants to remove wilting sections, keep them in size, or propagate them, you can cut them with a sharp knife.
Always wear gloves when working with this succulent and avoid touching the sap directly. Be sure to wash your hands afterward.
Instead of using a knife, a better choice is a pair of pruning shears. We recommend these shears.
Sterilizing Your Tools
Use sharp, sterile tools for the procedure to ensure the plant stays healthy and that the cutting process is easy.
If you have multiple plants and use your pruning tool on them, not sterilizing your tools can cause disease to spread between your plants.
The simplest way to sterilize your tools is to use isopropyl rubbing alcohol.
Anywhere from 70–100% will work. Dunk your tool in it or wipe your knife or shears with it.
Propagating Crested Euphorbia Lactea Cristata
Since the Coral Cactus plant is such a unique and sought-after plant, it may be hard to get your hands on one.
This is when you can propagate your own if you can get your hands on a Euphorbia lactea plant and a Euphorbia neriifolia or Euphorbia canariensis plant.
Best Method of Propagation
To propagate a Coral Cactus, you have to graft it yourself. They do not typically grow in nature.
It can be complicated, but the steps are simple and easy to follow. Because of the toxicity of the plants, wear gloves during the process.
How to Propagate Coral Cactus
So you have access to plants and sterile pruning tools. What’s next?
- Choose a healthy Euphorbia lactea and Euphorbia neriifolia plant. It is best to graft with younger plants.
- Cut the Coral Cactus’s crest off with a downward arrow shape.
- Remove the upper portion of the neriifolia, leaving a V-shape for the lactea to fit into. Make sure they will fit snugly, or the graft could fail and rot could grow.
- Join the two plants together, with the lactea now acting as the top of the neriifolia.
- Use grafting wax to seal the two plants together.
- Tie the plants together with rope or something similar.
- Clean the knife you used of any sap.
- It will take a few weeks for the plants to join together.
- After three or four weeks, you should take a look.
- Waiting longer to check is better than checking too soon.
- Remove the wax and the rope to see if the graft is holding.
- If it looks joined, leave the wax and rope off.
- If it still needs more time, put new wax and rope on it so the graft does not get damaged.
Once your plants have fully joined together, you have your Coral Cactus to enjoy.
Common Problems With Coral Cactus
Like most plants, Coral Cactus has several potential problems that can occur. These include leaf rot, pests, and disease. Here is how you deal with these issues.
Leaves Begin to Rot
If your Coral Cactus begins to rot, you should prune them, removing the decaying plant material.
Remember to use a sterile pruning tool. If you caught it too late, pruning may not help.
Curled Leaves and Dried, Brown Edges
Curled leaves and dried, brown edges occur due to too much sun exposure or under-watering. This can make it difficult to treat due to having to look into multiple causes.
When you get a new plant, slowly introduce it to more sun to let it get used to sun exposure to help prevent this issue from too much sun.
If the plant sees a lot of sunlight, you will need to do more watering. If it is spring or summer and you have not watered your plants in over two weeks, water them.
If it is autumn or winter and you have not watered your plant in more than a month, water it.
Color Changes to Pink, Purple, or Red
Your Coral Cactus changing to pink, purple, or red can be caused by too much sun exposure.
It is generally not something to cause too much worry. Just move your plant away from the sun for a while.
Pests
Spider mites are a pest you may have to deal with on your Coral Cactus. While they are not spiders, they have eight legs, making them arachnids like spiders.
The name comes from the webs they spin as protection from predators. You can sometimes only identify them with a magnifying glass due to their small size.
Where there is one spider mite, there are probably a lot of them, as they are colony pests.
You may find them more often in hot and dry climates, where these pests forgo the usually hot and human environment of most other common pests.
You may find them on your coral cactus because this is the ideal environment for succulent plants.
Spider mites feed on the leaves from the bottom, so you are likely to notice the leaf damage.
If your succulent has thicker leaves, check for them every so often to ensure they do not cause irreversible damage.
If the infestation gets too bad, entire leaves can fall off. It can be hard to get rid of spider mites, but some methods work.
There are natural predators like ladybugs that you can release to eat the spider mites, but you may not want more bugs in your house.
There are oils you can use. Neem oil is effective. Neem oil comes from the neem tree and acts as a natural pesticide.
It is very sticky. This might make it difficult to use on spider mites. You may struggle to apply it and it can drip down from the leaves. Ensure you remove the spider mites’ webs before starting.
There are also scale insects, but those are easier to remove. You can just use rubbing alcohol on the insects.
Diseases
Powdery mildew can occur in high humidity with low airflow. This fungus will damage the leaves of your plant. It thrives at the same temperatures as Coral Cactus, so you should look out for signs of it.
These include, but are not limited to:
- The look of dusted powder on its leaves
- Powdery mildew will look like white spots on the leaves of plants.
- The mildew harms the leaves.
- They can twist and become disfigured.
- The white spots grow on the leaves.
You can treat powdery mildew by removing the infected plant parts and disposing of them in the trash away from your plants.
Sterilize your pruning tool after pruning the infected parts. Leaving the powdery mildew on your tools or leaving the infected plant parts near your plants can cause the fungus to spread again.
FAQ
Euphorbia Lactea Cristata vs. Euphorbia Lactea
While Euphorbia lactea is the parent plant of the Cristata plant. It has not mutated or altered and has tiny, unbranched stems. On the other hand, the Euphorbia Lactea ‘Cristata’ has a rare mutation that causes it to “crest” or fan out, making it look like a coral reef. It has become a collector’s favorite. Botanists have attempted to recreate this mutation, but have been unsuccessful, whereas this mutation occurs naturally in the wild. ‘Cristata’ blooms infrequently, if ever. Typically, those that do have pink or purple blooms.
How big is Euphorbia Lactea Cristata?
As the Euphorbia Lactea Cristata plant matures, it can reach up to 36 inches in height and 24 inches in diameter. The primary characteristic of the plant is the huge, fan-shaped Cristata that grows at the top of the stem and can be multiple colors on the margins.
How often do you water crested euphorbia?
Crested euphorbia is a low-water houseplant that requires only intermittent watering (typically once every couple of weeks or so). The best advice is to water it when the soil feels dry and use well-draining soil.
Other Euphorbia Plants
The coral cactus is a fascinatingly unique plant. From its beautiful crown that mimics a coral fan to its simple care needs, it is well-loved.
The interesting history behind it makes it even more appealing. It is no wonder why so many people want it to join their collection.
However, there are other types of Euphorbia plants that you can plant. Check out our list of other types of Euphorbia succulents that can be grown either indoors or outdoors.
Euphorbia Obesa: These low-maintenance plants, often called “baseball plants,” “basketball plants,” and “living baseballs,” thrive with minimal water and moderate light. Euphorbia obesa is a good choice if you are looking for a low-maintenance, drought-resistant plant that will add a distinctive touch to your landscaping.
Euphorbia Flanaganii: It is a rare, evergreen, spineless succulent plant with long, wavy stems that resemble the serpentine hair of the mythical Medusa and is known as the Medusa’s Head. In contrast to the majority of succulents, it has horizontally spreading stems or branches that resemble snakes. Each has a Fibonacci spiral-like helix at its center, and no two are alike.
Euphorbia Hypericifolia Inneuphdia: Euphorbia HypericifoliaInneuphdia, also known as Diamond Frost Euphorbia, is an exceptionally resilient plant that can withstand practically everything. It is extremely low maintenance, and its lovely white blossoms do not require deadheading. It may be used in floral arrangements as a cut flower or grown on its own to provide texture and curb appeal to any front yard.
References
Lindsey Hyland grew up in Arizona where she studied at the University of Arizona’s Controlled Environment Agriculture Center. She continued her gardening education by working on organic farms in both rural and urban settings. She started UrbanOrganicYield.com to share gardening tips and tactics. She’s happy to talk about succulents and houseplants or vegetables and herbs – or just about anything in a backyard garden or hydroponics garden.