Two kinds of succulents were put together to make this strange plant that looks like a cactus. Depending on the top crest, it may have a fan of white, red, green, yellow, or purple succulent growth on top of what looks like a medium-green “stem.”
But this cactus is not a cactus at all, and treating it like one could cause problems. Let’s find out what this weird Frankenstein’s Cactus-That-Isn’t-Really-A-Cactus needs to live and grow!
All About Coral Cactus
The Euphorbia genus is a big family of about 2000 succulent plants that come from Africa. People often call them “spurges” because their latex, which is a poisonous sap, was used in the past as a purgative.
But the coral cactus is actually two different kinds of Euphorbia at the same time, which makes things a bit more complicated.
Euphorbia neriifolia, a plant that looks like a cactus and has large, oval leaves, is often used as the base. Even though other types of euphorbia are sometimes used, this one is by far the most common because it grows straight.
But the top will have a crest from a different plant. This is Euphorbia lactea, which is often called the “Cristata” variety. It has big, rippled leaves that look like fans.
It can sometimes bloom, but this doesn’t happen very often. The coral cactus flower is small and not very pretty, but when it does happen, it can be pink or purple. This is more likely to happen on older plants, and it might not happen at all.
The latex or sap from a coral cactus is poisonous and could kill you. This white, sticky sap can cause skin conditions like dermatitis and other irritations. If it gets into the eyes, it can hurt or even make people temporarily blind. If you eat it, it will make you feel sick and throw up.
Even though this latex will dry clear, it might still irritate your skin. When you touch this plant, it’s best to wear gloves. If you have to pick it up, hold the pot or use barbeque tongs to gently lift it without getting latex on your hands.
Many euphorbias have sharp spines at both the top and the bottom. These might also hurt, so keep an eye out for them, too.
Coral Cactus Care
If you treat your coral cactus like you would any other cactus, it might not be happy in your home. So, how do you care for this odd plant hybrid? Of course, by treating it like the mess that Euphorbia is!
Light and Temperature
It can be planted in full sun, but in hotter areas, choose moderate shade during the day to keep the plant from getting sunburned. To give a young plant time to get used to its new environment, it should start out in partial shade and be taught to accept more and more sun over time.
If you plant it indoors, choose a window that gets at least 3–5 hours of direct sunlight every day and turn it often so it doesn’t lean to one side.
Last, coral cacti can’t stand the cold. It doesn’t like it when the temperature drops below 50, but it does like temperatures in the 60s and above. If it gets too cold outside, move it inside, where it will be warmer.
Like succulents, coral cacti can’t handle frost or freezing. It will hurt the plant’s sensitive tissues and kill it.
Water and Humidity
“When in doubt, don’t water” is the golden rule for succulents and cacti.
But coral cacti are harder to grow than other cacti because they don’t do as well in dry conditions. At the same time, this plant does not like being wet. If your soil is too wet, root rot could happen to your euphorbia.
First, check how wet the soil is. If the top two to four inches of soil are dry, then the plant needs water. Don’t water the plant; water the soil until the water drains out of the bottom of the pot.
Overwatering could also be a problem, since too much water in the soil can lead to root rot, which will kill your plant. Always check the soil before you water!
When your coral cactus is growing quickly in the spring and summer, you should water it more often. During the fall and winter, you water the plant less often because it doesn’t need as much water at that time.
Even though it is picky about how often it is watered, your coral cactus will do well in a humid environment with enough airflow. This makes them great for growing in a greenhouse or indoors, but watch out for powdery mildew.
In general, Euphorbia plants need cactus potting soil or other very well-drained, gritty soils. They do best with a little bit of organic matter in the hole where they are planted, but cactus soil works just fine.
Coral cactus doesn’t care much about the pH of the soil, so it can grow in soil that is slightly acidic or slightly alkaline without changing much.
Grafted plants you buy in a store are often covered with gravel mulch, which is sometimes stuck together to help support the plant’s base during shipping. Even though this doesn’t hurt the plant, it makes it harder to tell if it needs water.
If you want to mulch, take out any gravel that is stuck together around the plant and replace it with loose gravel that can be moved out of the way. You can also get rid of the mulch all together. If the plant is outside, a gravel mulch can help keep weeds away and keep the soil from drying out too quickly.
During its growing season in the spring and summer, you should feed your coral cactus often.
Don’t fertilize your plant in the fall and winter because it doesn’t need the extra food. Slow-release or granular fertilizers should also be avoided because they can burn your euphorbia’s rootstock if they touch it.
Grafting A Coral Cactus
Most euphorbias are grown from cuttings that have been soaked in a hormone that makes them root, and only very rarely from seeds. But because the coral cactus is a grafted plant, the only way to grow more of them is to graft them, which is a bit complicated.
Start by choosing a healthy Euphorbia neriifolia and an Euphorbia lactea var. cristata to work with. Younger plants are much better at getting used to the grafting process than older ones.
Think about how the crest of the lactea looks and picture it on top of the base of the neriifolia. Find a couple who appear to be made for each other!
You will need to cut the neriifolia into a V shape, leaving enough of the sides to hold up the crown. For the Euphorbia lactea crest to fit inside the Nerium neriifolia stem, the bottom of the crest will need to be cut into an arrowhead shape.
When you trim, be careful to get a tight fit with no extra space. If there are gaps between the two plants, the sap will flow out, which could lead to fungal rots.
After you put your crest into the V of the neriifolia, use grafting wax to seal and polish all the surfaces where the two parts meet. Be very careful during this process to avoid getting sap from either plant on your skin. Always put on gloves.
Use thread to hold the Frankenplant in place at the point where the two plants were joined. It will take at least two to three weeks, and maybe even longer, for the two plants to grow together properly.
After 3 weeks, carefully remove the grafting wax and check the joint. If it still looks like it needs more time to heal, add more grafting wax and wait 3 more weeks before retying the twine to keep it in place. Make sure you don’t hurt your joint!
Coral cactus rarely gets rootbound when it’s in a pot. When you bring a grafted plant home for the first time, put on gloves and carefully take the plant out of its pot to look at it. As long as its roots don’t get stuck in the pot, it should be able to live there for a long time.
If there are signs that the roots are getting tangled, you can move it to a slightly bigger pot and add a little more cactus potting mix as needed. Make sure your pot has enough holes for the water to drain out.
Most coral cactus plants are grown in pots made of terracotta or other materials that let water drain out. In warmer weather, this means that they will dry out more quickly. While these are excellent plant pots, keep an eye on the water level.
Coral cactus hardly ever needs to be cut back. The only exception is if the cactus gets fungal rot, in which case it may be too late.
Rots caused by fungi can happen at the plant’s crown or its roots. If you see your crest getting darker or softer, this is often a sign of rot. If you are cautious, you can occasionally do surgery on the crest to remove fungal-damaged parts around the crest’s borders.
Coral Cactus Problems
Even though these plants came from strange places, they are not very susceptible to most growth problems. I’ll explain what a few could strike down below!
Your coral cactus might be reverting. When the Euphorbia neriifolia rootstock decides to try to rebuild as a neriifolia, a second stem or stalk grows next to the lactea crown.
If this occurs, you have the option of keeping it and creating an even more odd plant or carefully cutting it at the crest and letting the latex scab over the cut section. It should have no effect on the crown in any case.
The latex on coral cactus keeps many pests away because it smells bad. There are, however, a few that could hurt your plant.
Mealybugs and other scale insects do not discriminate between succulents; they attack all of them. Using insecticidal soaps on your euphorbias might harm the plant. Instead, eradicate these bugs with a cotton swab coated in rubbing alcohol.
When using rubbing alcohol in this way, it is best to use 70% rubbing alcohol, which is a little less strong. Higher levels of alcohol could cause the outside of the plant to catch fire.
Spider mites may also be found on coral cacti. Since you can’t use insecticidal soaps, spray the plant with a strong stream of water to get rid of spider mites and their eggs. Then, dry the plant completely on the outside. You could also use neem oil that has been diluted a lot.
As the latex sap dries, its inherent sealing characteristics protect it from most plant diseases. It also has some naturally occurring fungicidal properties.There are, however, a few things that could go wrong.
If there is powdery mildew, mix 1 tablespoon of baking soda with 1 gallon of water. You can put it on the surface of the plant.
Root rot could happen if the soil is too wet for your plant. To avoid this, use a potting mix made for cacti and don’t water them too much. Root rot makes it hard to save a coral cactus because the damage is usually very bad before the plant shows any signs.
If your plant was hurt by the cold, fungus could grow on its leaves. This usually shows up as leaves that are burned and soft. As we talked about above in the section on pruning, you might be able to cut off badly damaged parts of leaves at the edges.