Euphorbia Cactus
Candelabra Tree, Cactus Euphorbia
Euphorbia Cactus make for interesting and unusual houseplants that thrive on oodles of sunlight and a whole load of neglect from their owners!
They are also somewhat of a miniature version of their wild and free brothers and sisters that grow in the deserts of Southern Africa.
This sun-loving, fuss-free beauties range in size from a very modest one foot up to ten feet in stature.
Quick Guide
Position Maximum direct sunlight
Watering Water when soil is dry
Size One to ten feet (indoors)
Climate Minimum 23°F to 86°F (the warmer the better)
Propagate Stem cuttings (or seeds)
Seasonality Winter dormant
Toxicity Poisonous to people, cats, and dogs
Flowers Houseplants will not flower
Varieties of Euphorbia Cactus derive from the wide and varied group of plants that is Euphorbia. Whilst most are cactus-esque in appearance, to the trained eye, they differ greatly. Here’s how to tell the difference between a Cacti and a Euphorbia Cactus.
There are some distinct differences between the species of Euphorbia Cactus and a regular cactus. Firstly, their native homeland. Whilst both types of plants typically grow in the desert, the type of desert in which they inhabit are in totally different parts of the world. Cacti can be found growing in Mexico and some regions of South-Western America such as California and Arizona. Euphorbia Cactus on the other hand is native to regions of Southern Africa.
Possibly the most defining characteristic is the toxic milky sap that all Euphorbia Cactus (and indeed all Euphorbia plants) excrete when damaged or cut into. This latex-like substance is poisonous if consumed and can cause severe irritation if it comes into contact with the eyes and skin. These plants are best placed on high shelves so they are out of the reach of children and pets.
Cacti flowers are typically colorful and showy. However, Euphorbia Cactus flowers are small and bland. Bear in mind, it’s not possible for Euphorbia Cactus which are grown as houseplants to bear fruit or flowers. They are instead, grown for their pleasingly eye-catching shape and form.
For those wishing to identify a Euphorbia Cactus by its flowers in the wild, look out for tiny, non-showy flowers that are typically clustered close to the stem. They often feature bracts that look like bulbous petals.
Some Euphorbia Cactus such as Euphorbia Trigona or African Milk Tree as it is also known grow in the form of the quintessentially shaped cactus that most of us are familiar with.
During the summer growing season, however, it will produce spoon-shaped leaves. Most impressive!
These can be deadheaded at the end of the season but they do also shed naturally.
Another characteristic that clearly differentiates Cacti from Euphorbia Cactus is that all Cacti have areoles. Some species of Cacti are spineless and others will have spines protruding from these areoles. Euphorbia Cactus on the other hand do not have areoles even though, some species, will have spines.
The spines of Euphorbia Cactus are typically two-pronged and look a little like horns and these plants can also feature peduncles that can easily be broken off when gently rubbed with a hand or finger.
Euphorbia Cactus Care
When grown in their native homelands of the deserts of Africa, Euphorbia Cactus can grow to giant proportions of up to 30 feet in height. In the wild, they are accustomed to barren scrubland and intense heat so if you are growing one of these as a houseplant make sure you find the sunniest spot in your home for them and keep watering to an absolute minimum.
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Position
Euphorbia Cactus will languish in the bright sun all day long without the worry of scorching or fading in color. A south-facing window ledge is perfect and there is no need for a shroud between the window and the plant.
This plant is a true sun worshipper. Just remember to turn it slightly from time to time so it grows evenly rather than slanted towards the sun’s rays.
Height & Spread
In the wild Euphorbia Cactus resemble more of a tree than a plant or shrub as they tower over the desert shrublands of Southern Africa at heights of up to 30 feet.
When grown as a houseplant, Euphorbia Cactus is far more modest in stature. Whilst they can still grow impressively large, they will reach between one to ten feet depending on the species and how much sunlight it receives.
Watering Euphorbia Cactus
This species of plant is very rarely thirsty. They are used to the dry, arid conditions of the desert and are accustomed to very little rainfall.
As with all desert-dwelling plants such as succulents, Euphorbia and Cacti, they store water in their stems and leaves in order to withstand long periods without any water at all.
Euphorbia Cactus are winter dormant meaning they will grow very little in colder months and will therefore need even less water and nutrients during this time. You may even find that you do not need to water your plant at all in winter.
During the growing season, only water your plant when the soil is almost completely dry. I always advise against a regular watering schedule for Euphorbia Cactus preferring instead to check the moisture levels in the soil every two weeks or so.
You can simply insert two fingers at least 2 inches into the soil to see if it is completely dry. Alternatively – and always a good idea if you are a little overzealous when it comes to watering your plants – invest in a soil moisture test kit. This takes the guesswork out of your plant’s watering needs and can be used to test the moisture levels of all your plants.
If the soil deep below the surface is dry, then you can go ahead and water your Euphorbia Cactus. If it is not dry and remains moist to the touch, then hold off watering.
I find that a long-spouted watering can that directs water flow straight to the soil is a good idea when watering any succulent plants. This is because any water that remains on the leaves or stems can cause rot if the sun is not hot enough to evaporate it quickly.
Signs of overwatering include brown, yellow, or mushy leaves or even soil that remains damp for too long.
Euphorbia Cactus are also not good with humidity. Just like water that remains on their leaves and stems, a water-rich atmosphere will cause rot and do long-term damage to your plant.
Although unlikely, an indicator of under-watering is when your plant appears wilted or floppy and leaves – if present on your variety of Euphorbia Cactus that look droopy.
Soil
Did I mention that Euphorbia Cactus only like dry and arid conditions? I think I may have done, but in case you need reminding, they do, and this means well-draining soil that allows any excess moisture to drain away from roots effectively.
Always mix minerals such as grit, sand, or perlite with a peat-free or coco-coir-based soil. It is imperative that these types of plants get the oxygen they need to encourage healthy growth and prevent root rot and disease.
I tend to buy cactus soil and add in extra minerals to get a mix that is as well-draining as is needed for plants such as these that need such little amounts of water. Espoma Cactus Potting Mix is my go-to.
This one has Espoma’s patented myco-tone formula that helps to aerate the soil so that roots stand a better chance of being kept dry. It does contain perlite but even so, I like to add more to help further with drainage.
You can, of course, make your own well-draining soil at home fairly easily and relatively cheaply. Simply, mix two-thirds of minerals such as grit, sand, and perlite, and one-third of organic matter, such as a good quality peat-free compost or coconut coir.
I always add a layer of grit on top of the cactus soil to assist even more with drainage and I also think that it adds to the aesthetics of desert-style houseplants.
Flowers
The beauty of the Euphorbia Cactus lies in its cactus-like shape and form rather than its ability to produce flowers. In fact, these plants will only produce fruit and flowers in the wild. And even then, flowers are unimpressive, small, and bland.
In their native environment, flowers appear in summer. They are tiny, non-showy, and typically clustered close to the stem. They look like they have petals, but they are in fact bracts (leaves). These tend to be the most colorful part of the display.
Feeding
Euphorbia Cactus only need fertilizing in Spring and then every two months thereafter until the end of summer. There is absolutely no need to fertilize these plants during their winter dormant period.
Use a fertilizer that can be diluted to half strength and make sure you direct the fertilizer toward the soil rather than anywhere near the plant. Too much fertilizer can cause damage to the stem, leaves, and roots if over-fertilized.
There is a good range of cactus and succulent fertilizers available to buy that are specific to the feeding needs of dessert-loving plants.
How to Prune Euphorbia Cactus
One of the best things about owning a Euphorbia Cactus plant is watching its form evolve into the cactus-like shapes that are synonymous with, well cacti. It is unlikely, therefore, that this variety of plants will ever need to be pruned.
If you own a Euphorbia Cactus with leaves or spurges then there may be an occasion to prune back and deadhead as you see fit.
When pruning, always wear gloves and wear clothing that covers your arms and legs to avoid getting any of the toxic sap onto your skin or in your eyes.
If irritation does occur, always seek medical help immediately.
Repotting
Euphorbia Cactus is a slow grower and will not need repotting very often. If your plant does show any signs of becoming pot-bound where roots begin to grow from drainage holes or the plant looks to have outgrown its container then it is of course time to find a slightly bigger pot or container.
Simply re-pot in the replacement pot or container making sure it has good-sized drainage holes and always use fresh well-draining soil that you have mixed with extra grit.
Because these plants are so susceptible to root rot from excess water, it is a good idea to check the condition of the roots for any signs of rot whilst you have the plant out of its container.
Look out for wet and slimy, dark brown or black areas on the roots as this is a clear indicator of root rot.
You will need to gently trim away all traces of root rot using a sharp sterile knife or scissors. I always re-sanitize the cutting tools after each snip to minimize the risk of spreading the disease to healthy parts of the roots.
Always use gloves and cover arms and legs when handling to avoid causing irritation to the skin and seek medical help if any sap does cause irritation or gets in the eyes.
How To Propagate Euphorbia Cactus
If you are thinking of propagating Cactus Euphobia the chances are you’ll need to do so by stem cutting since seeds are so hard to come by unless you have access to those grown in the wild.
Stem-cutting propagation is straightforward enough and results are faster if you propagate in the summer months when it is generally warmer and the plant is actively growing anyway.
First, find a healthy-looking stem. The length of cutting you take will depend on the species of Cactus Euphobia to are propagating from. It needs to be long enough to stand proud of a small pot that has been filled with a mineral such as a perlite.
Use a sterile and sharp knife or pair of scissors to take your cutting and always wear protective clothing to avoid irritation from the toxic sap.
Allow the cutting to callous over for 2-3 days. It needs to be completely dry before it is planted.
Once it has calloused over dip the cutting in rooting hormone.
Take a small pot and use a mineral such as a perlite or grit to backfill around the cutting so it is firmly planted. You need just the top half to one inch of stem cutting to be protruding.
Place in a warm spot with plenty of bright, natural light and water only when the grit or perlite is dry. You’ll need to be patient but before long new roots will form.
Common Problems With Euphorbia Cactus
The milky latex-like sap produced by Cactus Euphorbia acts as a good deterrent to many insects and bugs which means it is less susceptible to disease and infestation. That’s not to say that these plants are completely pest resistant and there is always a possibility of an infestation. Here’s all you need to know about dealing with them.
Mealybugs
Mealybugs are tiny, wingless insects that are found in the crevices, ridges, and base of the spines of Cactus Euphorbia plants. These pests love humidity so if you find them on any dessert-loving plant it is a good idea to reduce the humidity levels or move your plant to an area that is dry and away from other plants.
Rather charmingly these little pests feed on the sap of your plant using their straw-like mouths to puncture into the foliage.
Mealybugs are easily detected because of the distinctive cotton-like mass that they produce on the surface of plants. Their infestation is never pleasant to look at, but, if treated quickly they won’t do any lasting damage to your plant.
To rid your Cactus Euphorbia of these tiny pests dab them off using a Q-tip that’s been soaked in diluted rubbing alcohol (such as surgical spirit). It’s a good idea to do this daily to dab away any visible traces until they are all completely gone.
In addition, every 7 days use a household insect spray, detergent, or soapy water to wash the mealybugs away until the infestation ceases. You will need to airdry your plant well to avoid excess water pooling or getting trapped in the crevices of your plant and doing more damage.
You can also use Neem oil to help discourage future mealybug infestations.
Scale
Scale insects don’t move. They can be found in the same places as mealybugs such as crevices, ridges, and at the base of spines. And, just like mealybugs, they feed on the sap from within the plant.
Plants tend to look rather wilted during an Infestation but if treated quickly enough, they will recover well.
Treat scale as I have described above for treating mealybugs.
For any infestation, you should always move the infected plant away from all other plants to avoid further issues. It’s also a good idea to give your other plants a thorough check and treat if needed.
Overwatering
There are a number of ways to overwater a Cactus Euphorbia. Firstly, giving it too much water. Next is not using well-draining soil mixed with a mineral such as grit or perlite and the final way is not allowing water to drain through the drainage holes of the pot after it has been watered, thus allowing the plant to sit in wet soil.
Any of these methods of overwatering is a surefire way of cutting short the life expectancy of your plant. If your plant is looking wilted, or is feeling soft to the touch and has brown, yellow, or mushy leaves, or if you are noticing that the soil is remaining damp for too long then you need to take action immediately.
Remove the plant from the pot immediately and brush away all of the excess soil. Have a thorough inspection of the roots for any sign of root rot. Roots that are brown or black and soft and mushy are rotten and need trimming off.
Use a sharp sterile knife or scissors to trim off the diseased roots. It is best to re-sanitize the knife or scissors after each cut to minimize the risk of spreading the disease to healthy parts of the roots.
Allow the cut roots to dry before repotting with fresh well-draining potting soil that contains plenty of grit or perlite and make sure you have sanitized the pot or container too. You may need to use a new pot or container if you think the drainage holes are not big enough on the previous one.
Resume watering your plant, but much less frequently from now on.
Remember, always use gloves and cover arms and legs when handling to avoid causing irritation to the skin, and seek medical help if any sap does cause irritation or gets in the eyes.
