Coral Cactus | Euphorbia Lactea Cristata Plant Care

Euphorbia Lactea Cristata

Coral Cactus

It’s difficult to know where to begin with this beauty.  But let me explain from the start that this plant is actually two distinct varieties of succulent Euphorbia that have been grafted together by hand to create this unusual variety. 

The vertically straight cactus-like stem is typically taken from Euphorbia neriifolia and the top section with its wide fan-shaped leaves that have the appearance of ocean coral is grafted from Euphorbia lacteal. 

The leaves can vary in color from green to purple, yellow, white, and even red.  Most often Euphorbia lacteal ‘Cristata’ is used for the top section which is recognizable by the rippled effect on the leaves. 

Quick Guide

Position Part Sun, Part Shade

Watering Water infrequently without allowing soil to dry out

Size Up to 4 ft in height if grown indoors

Climate Not Cold-hardy, Zone 10a (Minimum 30° F | -1.1° C)

Propagate Grafting

Seasonality Evergreen, Winter Dormant

Toxicity Sap is toxic to humans and pets

Flowers Pink or purple flowers – rare

Other names for this unusual houseplant include crested euphorbia, candelabra plant, and crested candelabra plant, but with its cactus-like base and coral formation leaves, it’s no wonder this plant is most commonly referred to as Coral cactus.

As is the case with all Euphorbia varieties, the Coral cactus plant produces a whitish sap (or latex) if cut which will dry clear but remain toxic to humans and pets.  Both the leaves and the base also have very sharp spines that can cause irritation to the skin.

Extra care should be taken when handling Coral cactus because the toxic effects can include vomiting or nausea if ingested, severe skin irritation, and even temporary blindness if the sap gets in the eyes. It is strongly advised to wear gloves, arm and leg coverings, and protective eyewear when handling and to seek medical advice immediately if any adverse effects occur. 

Coral Cactus Care

Position

Coral cactus favors year-round warmer temperatures for maximum growth potential and it certainly grows much bigger if grown outdoors in hot and humid climates.  Aim for a position that provides partial shade during the hottest part of the day to avoid scorched or sunburnt leaves.

That being said, it is possible to grow this plant indoors without too much care and attention providing it is positioned in a sunny and bright spot throughout the day. 

Since this plant likes humid conditions, it’s possible to grow in a greenhouse.  Just look out for powdery mildew (a disease that causes white mold on succulents and other plants caused by high levels of humidity) and make sure there is good airflow as a preventative measure.

The ideal and preferred year-round temperature for Coral cactus is between 65 to 85° F if growing outdoors.  It is not cold hardy and cannot tolerate frost so with any signs of a drop in temperature, this succulent should be brought indoors. Any exposure to freezing conditions will almost certainly result in damaged leaves and may even kill this plant.

Spread

In hot and humid year-round climates, Coral cactus can grow up to 2 to 4 feet high and up to 3 feet wide.  More modestly, when grown indoors it may only reach 10 to 15 inches in height.  But let’s face it, size isn’t everything and this plant is still spectacular however big it grows. 

Watering

It’s fair to say that Coral cactus has more complicated watering needs than your average cactus or succulent.  Yes, it prefers well-draining soil to allow for dry roots, however, it does need watering before the soil gets completely dry.  The key is to check the dampness of the soil on a regular basis and water once the top 3 inches of soil is dry. 

Always water the soil around the base of your Coral cactus plant until water begins to seep through the drainage holes at the bottom of the pot.  Try to avoid getting water on the leaves as they can become susceptible to rot if they remain wet for too long. Use a long thin spouted watering can or soak the plant pot and drain well.

You can test the dryness of the soil by pressing your finger right into the soil.  Depending on how long your finger is, you’ll be testing for some dampness in the soil near the tip of your finger. 

If in doubt or the majority of the soil feels damp, it’s best to hold off watering and check again in a couple of days.  Always under-water rather than over-water to avoid leaf or root rot that may become detrimental to the health of your coral cactus. 

Signs of overwatering include brown, yellow, or mushy leaves or even soil that remains damp for too long.  An indicator of under-watering is a plant that appears wilted or floppy with the leaves of your Coral cactus looking droopy.   

Coral cactus are winter dormant plants and will need watering less frequently in the autumn and winter months.  Increase the frequency of watering during the growing season from spring until the end of summer. 

Soil

Always use well-draining soil when planting and repotting Coral cactus.  The roots need to be free from excess moisture and you’ll only achieve this with peat-free soil or coconut coir mixed with minerals such as grit, sand, or perlite. 

Planting in the right type of soil will ensure your plant gets the oxygen it needs to encourage healthy growth, as well as helping to prevent root rot and disease.

Making your own well-draining soil can be done at home fairly easily and relatively cheaply.  Simply, mix two-thirds of minerals such as grit, sand, and perlite, and one-third organic matter, such as a good quality peat-free compost or coconut coir.

You can of course buy a ready-mixed version and there are plenty of good ready-mixed succulent and cacti soils available to purchase online or at any decent garden-supply retailer.

It’s a good idea to sprinkle a layer of grit on top of the cactus soil to assist drainage further.

Flowers

A flowering Coral cactus is a rarity and even when it does flower – which is often only seen in mature plants – there really is little to talk about, unfortunately.  Flowers are small and either pink or purple.  They can appear in spring and only very fleetingly. 

Feeding

To encourage a good, strong root system and healthy growth use a ready-mixed succulent or cactus fertilizer that has been diluted to 25%.  Fertilize every 2 to 4 weeks during the summertime growing season. Use a balanced 10-10-10 fertilizer.

There’s no need to fertilize during the dormant season of autumn and winter and always avoid using granular fertilizers as these can scorch the fragile tissue of your plant. 

Pruning

The joy of Coral cactus is watching its ocean coral-shaped leaves continually develop and evolve and so it is unlikely that your plant will ever need to be pruned.

However, since Coral cactus can be prone to leaf and fungal rot there may be an occasion where you need to take matters into your own hands by pruning away any diseased areas. 

Indicators of disease at the top part of your plant include yellow, brown, or mushy leaves and an early indicator of root rot can be a mushy stem just below soil level. 

When pruning, trim away any affected areas with a sharp, sterile knife, a razor blade, or a pair of scissors. Wearing gloves and long-sleeved clothing will ensure you avoid getting any toxic sap on your skin. 

Repotting

If your plant shows any signs of becoming pot bound or has outgrown its container, simply repot in a slightly larger container with drainage holes and always use fresh well-draining soil. 

Whilst you have the plant out of its pot check the condition of the roots for any signs of rot. If you do notice any wet and slimy, dark brown or black areas on the roots, gently trim them off with a sharp sterile knife or scissors.  Always use gloves and wear a long-sleeved top when handling the Coral cactus. 

How To Propagate Coral Cactus

Coral cactus itself is a grafted plant and requires delicate surgery and a little patience to perform at home.  Here’s a step by step guide of how to tackle it for yourself:

  • Taken from Euphorbia neriifolia select a healthy rootstock.  Cut a ‘V’ into the top section. 
  • Trim the stem of Euphorbia Lactea Cristata to form an inverted ‘V’ or arrow.
  • Slot the two Euphorbia cuttings together and tie them together carefully but securely with gardening twine. 
  • Lay the grafted plant on a layer of succulent soil and place it in a warm room in a bright position for 5-6 weeks. Avoid direct sunlight and move to shade if you suspect any scorching or sunburn. 
  • Check your plant from time to time to identify signs of the two grafts merging together. It may need another week or two if it has not completed joined together.
  • Once completely healed transfer your newly formed plant to where you will be growing it. Give yourself a pat on the back and water as instructed.

Alternatively, most reputable plant wholesalers will gladly source a Coral cactus for you to add to your collection if you’d prefer. 

If you are thinking of propagating euphobia it is best to do so by cutting.  This can be done quite simply by taking a healthy cutting using a sterile and sharp knife or pair of scissors and then dipping the cutting in rooting hormone. 

Always wear gloves and protective clothing on arms and legs in case the latex (sap) leaks onto skin or gets in the eyes and seek medical advice if this does happen.

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Common problems with Coral cactus

The sap produced by Coral cactus acts as a deterrent to many insects and bugs which means it is less susceptible to disease and infestation. Here’s an overview of some common problems with Coral cactus and how to handle them.

Root Rot

Overwatering your Coral cactus, or more to the point letting the soil stay wet for prolonged periods can lead to root rot. Unless you check your plant regularly one of the first signs of root rot is rotting leaves or a rotting stem.

To check for root rot, remove your plant from the pot and carefully brush off any remaining soil.   Roots that are brown or black and soft and mushy are rotten and need trimming off.  Allow the cut to dry before repotting with fresh soil in a clean pot. Resume watering your Coral cactus, but much less frequently.

Mealybugs

Mealybugs especially love humid conditions and can be found in the rippled leaves or in the crevices of stem junctions on Coral cactus and other succulents or cactus.

These tiny wingless insects produce a distinctive cotton-like mass on the plant’s surface. They feed on the plant’s sap by piecing their straw-like mouth into the foliage.

Use household insect spray, neem oil, detergent or soapy water to wash them away. Repeat regularly until the infestation subsides.

Aphids

A pest that breeds at lightning speed and one that feeds on the sap of plants. Aphids are most commonly green, white, or black. These slow-moving insects breed around new growth in astonishing numbers

They can be treated with a detergent or any household horticultural bug spray. This should be performed regularly until all signs of infestation have disappeared. 

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