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What Is Coral Cactus?
Coral cactus is the most common name for Euphorbia lactea cristata.
Contrary to what the name suggests, coral cactus is not a true cactus. Instead, the plant is a type of euphorbia that belongs in the Euphorbiaceae family. Botanically, coral cacti are related to the crown of thorns (Euphorbia milii), caput-medusae (Euphorbia caput-medusae), and the African milk tree (Euphorbia trigona).
Besides ‘coral cactus,’ Euphorbia lactea cristata goes by numerous other common names. Examples include crested candelabra plant, candelabra plant, crested euphorbia, crested Elkhorn, mottled spurge, mottled candlestick, frilled fan, dragon bones, milkstripe euphorbia, hatrack cactus, and false cactus.
The plant is noted for its crest-like appearance that looks a lot like ocean coral. That explains some of its common names.
Growing and Caring for Coral Cactus
Euphorbia lactea cristata will do well in cactus potting soil. You can also opt for gritty soils or other soil types that offer excellent drainage.
Coral cactus can tolerate dramatic fluctuations in soil pH. But for optimal growth, aim for slightly acidic or slightly alkaline soil. That’s anywhere between 6 and 8 on the pH scale.
Like most plants in the Euphorbiaceae family, the crested candelabra plant can thrive without fertilization. However, fertilizing the plants occasionally will accelerate their growth rate while also keeping them radiant all-year-round.
Fertilization is especially necessary during spring and summer. Apply a 10-10-10 water-soluble fertilizer that’s diluted down to a ¼ of its original potency (2.5-2.5-2.5) once every fortnight.
Avoid fertilizing your coral cactus plant during fall and winter or when the soil is visibly nourished. That would amount to overfeeding, which is nearly as harmful as underfeeding.
Also, avoid slow-release and granular fertilizers. These fertilizers could cause your euphorbia to burn.
The candelabra plant is a relatively small plant. That’s one of the features that make it an excellent addition to your indoor space.
Although the coral cactus can grow up to 16 feet in the wild, mature indoor candelabra plants will generally reach a height of 2 – 5 feet. So, you won’t have to worry about your beautiful green roommate growing into space-consuming monsters.
Although false cacti are reasonably hardy, these plants don’t tolerate drought conditions. Therefore, regular watering is necessary.
The ideal time to water your Euphorbia lactea cristata plants is when the soil is dry 2 – 4 inches deep. Do not wait until the leaves become wilted or droopy as that’s already a clear indication of dehydration.
Also, avoid watering the plants directly. Misting the leaves could offer a breeding ground for pests and diseases. Instead, water the soil until it runs out of the container base.
It’s also important to note that while coral cactus need regular watering, the plants will still prefer drier soils. Waterlogged soils may cause numerous growth problems, such as root rot.
Lastly, increase watering frequency during spring and summer as coral cacti undergo active growth periods during these months. You can then reduce watering frequency in fall and winter.
Euphorbia lactea cristata love humid conditions, such as greenhouses. If growing these plants indoors, you may need to invest in humidifiers to keep the indoor humidity high.
However, make provisions for sufficient airflow using ventilation systems and fans. Signs of powdery mildew indicate that your coral cacti are probably receiving more than their required humidity levels.
Coral cactus can flourish in varying light conditions, ranging from full sun to partial shade.
The conventional wisdom is to place the plants in direct sunlight during colder seasons and then shift them to areas that receive filtered light during hotter months. That will go a long way in preventing sunburning.
Also, remember to start new coral cacti plants in partial shade. You can then train the plants to take in more sun as they grow.
The crested euphorbia plant enjoys temperature ranges between 60 and 85 degrees Fahrenheit.
Being succulent in nature, coral plants will not tolerate frosty conditions. Chilly weather may damage the fragile tissues of your crested euphorbia plant, ultimately killing it.
As a best practice, ensure your indoor temperature doesn’t plummet below 50 degrees Fahrenheit.
Pests and Diseases
Crested Elkhorns may be resilient alright. But these plants are not immune from pests and diseases.
Common pests that plague coral cacti include scale insects and mealybugs. You can also expect spider mites invasion from time to time.
Thankfully, these pests are easy to remove using readily available home remedies like alcohol solutions. Gently apply a slightly diluted alcohol solution to the plants using a cotton swab. Avoid concentrated alcohol as that could burn your plants’ exterior.
You could also control mottled splurge pests by applying a firm spray of water directly to the plants. This helps to remove the pests along with their eggs. However, ensure the plants dry thoroughly after. Heavily diluted neem oil is another effective remedy you can use to keep pests from your indoor coral cacti plants.
In terms of disease, crested Elkhorns are susceptible to fungal infections like root rot. You can minimize the risks of these diseases by keeping the plants dry (but not water-deprived).
The milkstripe euphorbia generally doesn’t require pruning. The only time you’d need to prune your coral cacti is if the plants develop fungal rot.
Fungal rots typically affect the crest or roots of milkstripe euphorbias. Tell-tale signs include browning or softening of the crest.
A gentle surgical procedure can help to clear the plants of the decayed parts. Remember to use a sterile razor blade and wear a pair of protective gloves. That will protect your skin from dangerous contact with the toxic latex produced by coral cacti.
After removing the damaged parts, your coral cacti plants should recover. You don’t even need to dress cut surface as the latex secreted by the plant will form a scab around the wound.
Dragon bones aren’t known to become rootbound in a pot. So, repotting is rarely a serious concern.
Just be sure to plant your coral cactus in a breathable pot like a terracotta. Such pots allow excess water to evaporate, thereby preventing root rot.
If ever your dragon bones show signs of root entanglement, you can always transfer the plants to a larger pot with proper drainage.
Most euphorbias are propagated by cuttings as opposed to seeds. However, the mottled candlestick can only be propagated by grafting. The process should typically unfold as follows:
i. Put on a pair of safety gloves to protect your skin from the plant’s toxic latex.
ii. Choose a healthy young Euphorbia lacteal and Euphorbia neriifolia.
iii. Make a V-incision into the base plant
iv. Remove the upper portions of the cutting but ensure there are enough stem sides to anchor the crest.
v. Make an arrowhead cutting of the stem of your Euphorbia lacteal plant.
This ensures that the cut section fits snugly into the Euphorbia neriifolia plant. Do not leave any space between the two plants as that would encourage leaking of the latex and possibly cause fungal rots.
vi. Attach the two plants and cover the joint using grafting wax.
vii. Reinforce the joint using twine.
viii. Allow for between 2 and 3 weeks for the two plants to fuse together.
ix. Remove the twine after three weeks and inspect the joint.
If the plants don’t appear to have fused completely, apply fresh wax to the joint and retie the twine, then check again after three weeks.
Coral Cactus Flowering
Euphorbia lactea cristata rarely produces flowers. Even when it does, the flowers are generally tiny and largely inconspicuous.
Most coral cacti will bloom when they’re reasonably mature (at least one year old). If the flowers appear, they’re usually purple or pink.
Coral Cactus Toxicity
All euphorbias secrete a latex sap. The sap is traditionally used in folk medicine as a purgative.
However, the sap can irritate the skin upon contact. It’s worse if the substance finds its way into your eyes. Besides severe pain and irritation, the sap may also cause temporary blindness.
Ingesting coral cactus sap is not safe either. The compound can cause nausea, vomiting, and diarrhea in humans and animals alike.
Therefore, it’s important to proceed with extreme caution while handling coral cactus sap. It’s also best to position the plants in spots least frequented by your kids and pets.
In addition to the latex sap, the coral cactus also contains sharp spines that can easily break the skin. A stab by these spines makes it easier for the toxic latex sap to penetrate your skin.
Coral cactus is a fairly hardy and beautiful plant that will look great in your indoor space or wellness garden.
Implementing the above-listed tips will go a long way in helping your Euphorbia lactea cristata plants achieve optimal growth.