Euphorbia Trigona: African Milk Tree Exotic and Sometimes Dangerous

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African Milk Tree cactus (Euphorbia trigona) is a tall, rugged, easy-care plant with thorns.

The African milk tree (Euphorbia trigona) is native to Central Africa. It is often grown as a hedge due to its rapid and enthusiastic growth.  

Euphorbia trigonia - African Milk TreePin
African Milk Tree – potted in rustic containers | via the Borrowed Nursery

It should come as no surprise that many people think of it as an African cactus.

Quick African Milk Tree Care Guide

  • Botanical Name: Euphorbia trigona – (yoo-FOR-bee-uh) (try-GOH-nuh)
  • Common Name(s): African Milk Tree cactus, candelabra cactus, Abyssinian Euphorbia, cathedral cactus, friendship cactus
  • Synonyms: Euphorbia Cactus, Euphorbia Trigona Rubra
  • Family & Origin: Euphorbiaceae family, native to Central Africa
  • Growability: Easy with a slow growth rate
  • Grow zone: USDA zones 10-12
  • Size: Outdoors 7′-9′ outdoors and 2′-4′ feet tall indoors
  • Light: Bright, indirect sunlight
  • Humidity: Tolerates low humidity
  • Temperature: Prefers 35°-90° Fahrenheit
  • Water: Well-draining cactus or succulent soil
  • Fertilizer: Feed monthly a balanced, water-soluble fertilizer in spring and summer.
  • Soil: Well-draining succulent soil
  • Pests & Diseases: Susceptible to mealybug, plant scale, root rot
  • Propagation: Stem cuttings
  • Toxicity: White milky sap is a skin irritant and poisonous. Protect eyes and mouth when handling. Wash immediately if in contact with the skin. Keep pets or children away.

This thorny succulent hails from West Africa, growing wild in dense, thorny thickets.

In its natural habitat, the African Cactus Milk Tree (aka Abyssinian Euphorbia) has a variety of landscaping and gardening uses.



Close-up of a green cactus with small red-brown leaves and white spines against a blurred background.Pin
Photo Credit: Instagram @birbnerd_swest28

In the United States and other areas, it is grown as an indoor plant and used as an attractive addition to cactus and succulent gardens in warmer areas.

While the succulent African milk tree may be grown successfully in USDA hardiness zones 8 and 9 with winter protection, it flourishes best in USDA hardiness zones 10 through 12. 

In this article, we will discuss the characteristics, care, and uses of this interesting plant. Read on to learn more.

Why Isn’t Euphorbia Trigona A Cactus?

The African Milk Tree is considered a succulent plant even though they have leaves. Cacti (with the exception of Christmas and Easter Cactus) do not grow leaves.

The leaves of the African Milk cactus are small and short-lived.

They grow along the ridges that make up the corners of the plant’s rectangular stems. Thorns also emerge from these ridges.

The thorns grow in sets of two, and single leaves emerge from between them.

When grown outdoors, the plant may produce small white or yellow flowers. Indoors, it is unlikely to bloom.

A tall green cactus with small leaves in a decorative terracotta pot against a white background.Pin
Photo Credit: Instagram @fern_and_ivy_plants

Why Is The Trigona Called A “Milk Tree”?

The African Milk Tree plant is a member of the genus Euphorbia, part of the family Euphorbaceae. All of these plants exude a poisonous white sap when cut or broken.

For this reason, it’s a good idea to keep them out of the reach of kids and pets and to keep your skin and eyes well-protected when pruning, repotting, or otherwise handling the euphorbia cactus.

The sap can cause serious skin and eye irritation on contact, as well as severe gastric distress if ingested. [source]

This plant caution also holds true for the red variety Euphorbia Trigona Rubra or “Royal Red.”

Is The African Milk Tree Really A Tree?

These big succulents outdoors are tree-like. They can grow as high as 9 feet and grow in a characteristic “candelabra” shape, giving them the appearance of a tree. 

Two zig-zag cacti with green stems and purple-edged leaves against a pink wall.Pin
Photo Credit: Instagram @soofs_jungalow

It may also explain some of the plant‘s common names:

  • Candelabra Euphorbia
  • Euphorbia cactus
  • Candelabra cactus

You can control the plant’s growth somewhat by cutting or breaking off stems, which you can plant in their own pots, using a light, sandy soil to grow more “trees” to share with friends.

How To Propagate Euphorbia Trigona

Propagation of this hardy succulent couldn’t be easier. Visually survey your Euphorbia trigona before you begin and decide which new stems or sections you want to reduce.

Be sure to put on rubber gloves and protect your eyes with goggles, then break or cut sections of the parent plant. Sections used for rooting should be about three or four inches in length.

Don’t Try This At Home!

In this video, an intrepid gardener shows a very daring way to take cuttings!

Although he experiences no mishaps, you can see that he puts himself in great danger of having sap drip from a very tall and vigorous plant onto his bare skin and into his eyes!

Making Euphorbia Candelabra Cactus Cuttings

Luckily, this operation turned out alright, but it’s easy to see that these plants produce copious amounts of potentially dangerous sap.

When you take cuttings, be sure to have a damp cloth on hand to wipe up weeping sap. Wear gloves, goggles, and long sleeves, and be careful not to let the sap come in contact with your skin or eyes.

Related: Read our article on Cactus Propagation here.

Once you’ve taken cuttings, lay them on paper towels, newspaper, or some other disposable, absorbent material.

Allow the sections to dry out and harden off for a week in a cool, dry place, out of direct sunlight. After your cuttings have hardened off, plant them in an airy, sandy, well-draining potting soil that is not too fertile.

You needn’t worry much about pH level as Euphorbia trigona grows in acidic, neutral, or alkaline soil.

This drought-tolerant plant enjoys a dry or arid climate and can withstand fairly hot temperatures. 

If your growing environment experiences hot summers, locate the plant in a spot with indirect sunlight or partial shade to avoid overheating. 

This plant doesn’t need extra humidity, and growing it in a humid climate may cause stress, leading to fungus or pest infestation.  

Water when you plant the cuttings, and keep the soil lightly moist until signs of rooting and growth appear. At this point, you can reduce watering and begin treating the cutting as an adult plant.

leaves up close of the Euphorbia cathedral cactus (euphorbia trigona)Pin

Euphorbia Trigona Care

Once established, Euphorbia trigona is an easy-care plant. It’s best to provide lots of sunlight and/or artificial light. If you’ve grown Euphorbia milli (Crown of Thorns), you’ll do fine.

These plants can do very well, like Euphorbia milli Crown of Thorns and Euphorbia tithymaloides “Devil’s backbone,” as houseplants year-round in medium light settings and normal household temperatures.

By gradually transitioning Euphorbia trigona to more sun, you can enjoy the African milk bush in the great outdoors during the spring and summer.

Transition the plant gradually so it acclimates to more sun, air movement, and temperature fluctuations. Choose a sheltered area that gets filtered sunlight or partial sunlight for potted and container plants.

An area that receives full sun is suitable as long as the summers are not consistently hot. In this instance, extra watering may be needed to offset the hot, bright sunlight.

If you live in a semi-tropical or desert area where temperatures will be unlikely to drop below 50° degrees Fahrenheit and never freeze, plant Euphorbia trigona directly in the ground.

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A southern-facing window works well for indoor growing, as does an outdoor spot that receives partial sun. In this case, choose a fairly sheltered location that receives full sun or part shade.

If you need to move your Euphorbia trigona outdoors or repot as a container plant, it’s best to do so in the springtime.

Sandy soil or potting mix formulated specifically for succulents allows for the best water drainage, especially when pumice or perlite is mixed in.

Too much water can cause rot. Soggy soil needs to be avoided. If after you water it, there is still water in the pot or container after half an hour, make sure you pour the excess away.  

Place the pot in a warm area with sufficient light and a temperature between 65 and 75 F, but out of direct sunlight.

You can groom the parent plant and take cuttings while making the transfer, just like when handling the – Euphorbia Tirucalli (firestick plant). Remember to wear protective gear to prevent accidental stabbings and sap contact.

A green cactus with small leaves in a colorful patterned pot against a white wall.Pin
Photo Credit: Instagram @planted_souls

Grooming is easy with Euphorbia trigona. Just break or cut off stems that don’t seem to fit in. Remove any branch that protrudes and might break off accidentally as people walk past.

If accidental contact with sap does occur, be sure to wash well immediately to avoid irritation. If the sap gets in the eyes, it should be flushed out with running water, and a visit to the emergency room would not be overly dramatic.

Water: Because Euphorbia trigona are succulents (not cacti), they do not tolerate complete drought. But they don’t like wet soil! Keep the soil very lightly moist during the growing season (spring and summer).

So you ask – “How often do you water succulent plants?” On trigona, if the top couple of inches of soil feels dry, deep watering is in order.

African Milk tree prefers a sand-rich, well-draining soil combination. You can also add two parts of potting soil, vermiculite, perlite, or good gravel, to the soil mix, as well as one part of peat moss.

Just be sure the plant does not stand in water, as this can lead to rotting roots. Make sure your “clay pot” has drainage holes.

A tall cactus in a terracotta pot with bird-shaped wall decorations in the background.Pin
Photo Credit: Instagram @plants.nature.love.aquarium

Try saving the plant by cutting off the infected stems. Yellowing or browning of the succulent may also indicate root rot from overwatering. 

Fertilizer: Provide Euphorbia trigona with a light feeding of balanced, water-soluble succulent fertilizer monthly during the spring and summer. Reduce watering and do not fertilize at all during the cooler months (fall and winter).

Liquid fertilizer also helps you to control the dose of fertilizer. This prevents overfertilizing. 

How To Deal With African Milk Tree Diseases and Common Pests 

A healthy African milk tree is usually not susceptible to pests or diseases. However, watch for the cotton-like threads made by mealybugs. 

African Milk Tree is relatively hardy and resistant to disease and pests as long as it is well cared for. You can also use a paper towel and rubbing alcohol to remove bugs or spray off the bugs with water from a garden hose.  

Avoid waterlogging the soil and provide the plant with good sunlight and air circulation. This will go a long way toward preventing problems. Weakened Euphorbia trigona may be susceptible to:

Mealybugs

If you see cotton-like threads forming on the plant, wipe them off with a paper towel soaked in rubbing alcohol. 

To remove mealybugs, use insecticidal soap or apply rubbing alcohol directly to the area of the infestation using a cotton swab.  

If you have a massive infestation, wipe the mealybugs off and spray the plant with a natural insecticide, such as a Neem oil insecticide spray solution.

Plant Scale

Plant Scale bugs: These tiny insects are covered by a nearly impenetrable brown shield. This makes it difficult to remove them.

Like the mealybug, wipe them off firmly with a paper towel soaked in rubbing alcohol. If this doesn’t work, scrape them off gently with a knife blade. 

A Neem oil solution can be used to ensure they are gone and prevent their return.

Related: More on getting rid of scale on succulents

Fungal Infection Cork Disease

Cork disease is a fungal infection. If you see patches of cork-like material on the stem, it is an indication of overwatering and/or soil that is too rich.

If you’ve kept cuttings and have replacement plants, it is best to dispose of the diseased plant.

If you are dead set on saving it, prune Euphorbia trigona with a very sharp, sterilized knife or shears to completely remove the damaged areas and dispose of them in the trash (not the compost heap).

Paint the cut areas with a plant fungicide. Repot the plant into a cactus soil mix and keep it in a consistently warm and airy location.

Reduce watering. You may not be able to save the Euphorbia cactus, but keeping it warm and well-ventilated will give it the best chance of survival.

Rot or Fusarium Wilt

Fusarium wilt and rot are other fungal infection that come from the soil. If your plant displays soft, reddish patches around the base of the stem, suspect fusarium rot.

Most of the time, it is fatal, and disposing of the plant, pot, and all is the best solution. If you keep the container, be sure to sterilize it before using it again.

If you must save the plant, follow the steps outlined for cork disease. [source]

Hardy Euphorbia Cactus is Virtually Problem-Free

All in all, caring for African milk plants is amazingly easy. Begin by choosing a healthy plant (or cutting) with no soft spots or signs of pests.

Three Zamioculcas zamiifolia plants, also known as ZZ plants, in marble patterned pots on a wooden surface near a window.Pin
Photo Credit: Instagram @tmwildflowers

If you acquire a potted Euphorbia trigona plant, check to be sure the root system and root ball hold the plant in the pot firmly. Make sure the plant has not been sitting in water.

If you begin with a well-cared-for plant and continue to provide it with well-draining soil that’s not too rich, lots of sunlight, and an airy setting, it should grow well and provide you with lots of healthy cuttings for many years.

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