Euphorbia lactea cristata [yoo-FOR-bee-uh, lak-TAY-uh, kris-TAY-tuh] or Coral Cactus is not a cactus.
Instead, it is a type of Euphorbia plant belonging to the family Euphorbiaceae and related to the:
- Crown of Thorns (Euphorbia Milii)
- African Milk Tree – Details on Euphorbia trigona care
- Caput-Medusae (Euphorbia Caput-Medusae)
The plant has an interesting crest-like appearance very similar to ocean coral and explains the plant’s common name.
Other common names include:
- Crested Candelabra Plant
- Crested Euphorbia
- Candelabra Plant
- Crested Elkhorn
The Euphorbia genus is comprised of more than two thousand different types of succulent plants, most of which originate in Africa.
Coral cactus has its origins in the nurseries of experimental horticulturists because it is actually a grafted combination of two of these types of Euphorbia, Euphorbia lactea, and Euphorbia neriifolia.
The crest of the Euphorbia lactea is grafted onto the root and stock of the Euphorbia neriifolia.
Occasionally, this type of long-lived, perennial houseplant is created by grafting the crest of the Euphorbia lactea onto the actual cactus stock.
Coral Cactus Care
Size & Growth
Crested Euphorbia is a small houseplant.
It rarely reaches a height of more than about 2′ feet.
The interesting and unusual ‘foliage’ is the real drawing card of this fascinating plant.
The top crest has ruffled edges, which may be green, red, purple, white, or yellow.
Crested Candelabra plant very rarely produces flowers, and when it does, the flowers are very small and fairly unnoticeable.
The tiny blossoms may be pink or purple.
If you wish to encourage flowering, you’ll need to wait until your plant is fairly mature (at least a year old).
If flowers are to appear at all, they will do so in the springtime when the weather is quite warm.
Light & Temperature
Crested Elkhorn likes to be kept in bright, indirect sunlight.
Indoors, a bright window (south) is a good location.
Be sure to turn your plant occasionally to prevent having it grow in a lopsided manner.
Outdoors, it can do well in full to partial sun.
If you live in a very hot area, a location with bright, indirect sunlight (e.g., under a tall tree or on a covered porch or patio) is advised.
If you keep your plant indoors during the cold months and move it outdoors in the spring and summer, be sure to transition it slowly to avoid burning the delicate tissues.
The ideal temperatures for this plant are between 60° and 85° degrees Fahrenheit (15° – 30° C).
When temperatures begin to drop below 50° degrees Fahrenheit (10° C), you should bring your plant indoors.
Coral Cactus is winter hardy in USDA hardiness zones 10 through 11.
Watering & Feeding
Like all Euphorbia, Crested Candelabra likes porous, well-draining potting soil kept slightly moist.
Learn more on Soil for Succulents
Excessively dry soil will cause the crest to wither, and this damage is irreparable.
Excessively wet soil will cause problems with root and stem rot.
Check the soil frequently, and when the top couple of inches feels dry, it’s time for a deep watering.
Coral cactus typically needs more water during its active growing seasons, spring and summer, and less during the autumn and winter months.
Fertilize monthly with a balanced 10–10–10 liquid fertilizer, diluted to one-quarter strength, during the growing season.
Don’t use granular fertilizer or slow-release fertilizer because it is damaging to the plant’s roots.
Don’t fertilize at all during the autumn and winter.
Potting Soil & Transplanting
When you buy a coral cactus, you’ll probably find it’s planted in a ceramic container and may have a solid mulch of gravel glued together over the top.
You’ll want to remove the plant from this arrangement as quickly as possible.
A ceramic container will not allow good air circulation to the roots, and the solid mulch of gravel will prevent you from being able to check the soil moisture levels as often as you’ll need to.
Create the gritty, well-draining potting soil coral cactus loves by mixing coarse sand and a good quality soil in equal amounts.
Alternately, just use a cactus soil or succulent potting soil.
These plants are tolerant of all soil pH levels.
Repot your Crested Euphorbia into a terra-cotta pot with ample drainage holes.
When transplanting, add a little organic compost into the planting hole to provide some extra nutrition.
Grooming & Maintenance
A well-kept, healthy coral cactus needs no grooming at all.
Those kept outside with good air circulation may be given a shower with the hose every couple of weeks when you water.
This will help keep dust from collecting on the surface of the plant.
Otherwise, unless your plant develops a fungal infection, you will never need to prune it.
Since it is very slow-growing, it will seldom need to be repotted.
How To Propagate Euphorbia Cristata
It’s easy to purchase Crested Coral Cactus already grafted.
If you’d like to try creating your own, follow these steps:
- Obtain a Euphorbia lactea plant and a Euphorbia neriifolia plant.
- Cut an outward curving V-shape in the crest of the Euphorbia lactea and a corresponding V-shape in the rootstock of the Euphorbia neriifolia.
- Place the two sections firmly together and cover the entire outer area where the plants join with grafting wax.
- This will help prevent the wounded tissues from drying.
- After the grafting wax is dry, wrap rope or twine over the outside and tie it to hold the pieces together.
- Assuming the plants are compatible, the wounds should heal, and the plants should graft within a couple of weeks.
- When you see the plant is growing healthily, remove the twine and the wax.
- Don’t be too quick to do this.
- If the graft is not complete, the tissues could be damaged, and this could cause a major setback.
Details on the Euphorbia neriifolia plant.
Coral Cactus Pests or Diseases
If you water correctly, provide the plant good airflow and humidity, you should not have any problems with your coral cactus.
The latex sap of the coral cactus tends to protect against pest infestation.
In less than ideal settings, plants may encounter pests and fungal infections.
Common pests include:
- Mealybug Succulent bugs
- Scale Insects
- Spider Mites
If caught early enough, remove mealybugs and scale insects by simply wiping them off with a cotton swab dipped in 70% isopropyl alcohol.
Avoid using higher concentrations of alcohol as it may tend to burn the flesh of the plant.
Wash spider mites and their eggs away with a strong spray of water.
For heavy infestations, use a very light Neem oil spray solution.
Common diseases include:
- Powdery Mildew
- Root Rot
- Stem Rot
For powdery mildew, mix up the preparation of a tablespoonful of baking soda and a gallon of water. Use it as a spray.
You should also increase air circulation around the plant and reduce humidity.
For problems with fungal rot, cut away any mushy, brown parts of the plant and its roots.
Use a sharp, sterile blade and make very clean cuts.
There’s no need to apply a fungicide to the wounds as the plants’ latex sap contains fungicidal properties.
As it dries, it will create a scab to help protect the rest of the plant from infection.
Be sure to reduce watering and increase air circulation around the plant to prevent reinfection.
Is Lactea Cristata Toxic or Poisonous?
All Euphorbia have a poisonous, latex sap often used in folk medicine as a purgative.
Coral Cactus is no exception, so it should be handled with care and kept safely away from kids and pets.
The sap can cause skin irritation upon contact (even if it has dried).
If you get it in your eyes, it can cause severe irritation and may even cause blindness.
If it is ingested, it will cause nausea and vomiting.
Whenever you’re handling your crested Euphorbia, be sure to wear gloves and eye protection.
Avoid contact with the milky white sap, and be sure to wash up thoroughly when you’ve finished your task.
Also, watch out for sharp spines on this plant.
If you’re stabbed by one of the plant’s spines, it can cause the same sort of irritation as the sap.
Is The Cristata Coral Cactus Invasive?
This artificially engineered Euphorbia cannot be considered invasive.
It would not be possible for it to replicate itself in the wild.
There is, however, a genuine cactus (Cylindropuntia fulgida var. mamillata) which shares the common name, Coral Cactus.
This cactus is considered quite invasive in Australia.
Suggested Coral Cactus Uses
Crested Elkhorn’s attractive whorls of wavy, fleshy leaves make it an interesting addition to any collection of indoor houseplants.
This hardy and unusual plant adds color and texture to cactus arrangements.
On its own, it makes a lovely windowsill plant.
In USDA hardiness zones 10 through 11, Coral Cactus is a pretty garden addition year-round.