Euphorbia Trigona: African Milk Tree Plant Care

African milk trees might look a bit like miniature trees, with their triangle shape and thick waxy leaves, but they’re actually cactus.

That means that you need to treat them like succulents if you want them to thrive.

Thankfully, African milk trees are robust and fast-growing, even in moderately good conditions. So, these aren’t going to be your pickiest indoor plants.

In this article, we’re going to cover everything you need to know to help your Euphorbia trigona, or African milk tree, thrive.

What are Euphorbia Trigona African Milk Tree Plants?

Euphorbia trigona, also called the African milk tree, is a succulent plant commonly found in Central Africa.

The African milk tree is also called the cathedral cactus, candelabra cactus, friendship cactus, and African milk bush.

A healthy African milk plant is a drought-tolerant plant that does well both indoors and outdoors.

In fact, they are actually used as hedge plants in some parts of the world because they grow so fast.

Some Euphorbia trigona plants in the wild have been known to grow as tall as 15 feet!

However, you can expect a cathedral cactus to get between 7 and 9 feet tall when grown outdoors, but they average 2 to 4 feet tall when grown indoors.

What-Are-Euphorbia-Trigona-African-Milk-Tree-Plants

While Euphorbia trigona tends to be a very vertical growing plant and isn’t much wider at the crown than the base, you can grow several mature plants close together without too much competition, and more mature plants are likely to have more stems and branching that make them a little wider.

The stem of Euphorbia trigona has three distinctive sides, giving the plant a distinctive triangular shape. If your African milk tree has four sides and a square profile instead, you might actually have a related species, Euphorbia acrurensis.

Thriving African milk trees have dark, cool green stems, occasionally with a white or yellowish stripe down the middle of the stem.

Their leaves are a lighter shade of the same color, and the smaller leaves are lighter than the larger, more mature leaves.

Depending on how it’s been grown, they can have yellow flowers, but some varieties have a combination of white or yellow flowers.

With this in mind, don’t worry if your Euphorbia trigona does not flower; it is not a sign of poor health or needing more fertilizer; some plants may never flower.

African milk trees also produce a milky white sap that is contained mostly in the stem but also in the leaves.

This poisonous white sap can be irritating to the skin, so it’s important to wear protective gloves while working with Euphorbia trigona, and especially while handling fresh stem cuttings to propagate.

How to Care for a Euphorbia Trigona African Milk Tree Plant

Euphorbia trigona is relatively easy to keep healthy. Maybe that’s one reason Euphorbia trigona is sometimes called “good luck cactus or good luck plant,” since they’re so simple to care for.

Euphorbia trigona is a succulent plant that prefers bright light and warm and arid climates.

They grow relatively fast when water is plentiful but are drought tolerant and can even tolerate short periods of complete drought without damage.

Like most succulent plants, Euphorbia trigona needs well-draining soil but also prefers a good amount of water when you water them. But they do have a tendency to get root rot if they are overwatered.

The only challenging thing to note is that they produce a toxic milky sap when cut open.

Temperature and Climate

Temperature-And-Climate-For-A-Euphorbia-Trigona

African milk trees do best in areas that don’t get colder than 50 degrees at night and don’t get much warmer than 75 degrees during the day.

They are most tolerant of low humidity, but some moisture in the air won’t cause problems.

Since the African milk tree’s natural habitat is arid climates in Central Africa, it’s used to both fairly hot temperatures and minimal water during parts of its growing season.

This drought-tolerant plant enjoys warm temperatures over cold temperatures and sandy soil over wet.

When it comes to outdoor African milk tree care, Euphorbia trigona is hardy in USDA zones 9a through 12b.

Light

Light-For-Euphorbia-Trigona

An African milk tree will typically do better with bright sunlight, but it can still thrive with indirect sunlight.

You should avoid planting your African milk tree anywhere with partial shade unless the light in your area is very intense and warm, or if you’re willing to supplement the natural light with grow lights.

Indoors, Euphorbia trigona benefits from indirect sunlight from windows, but a healthy plant can also grow well with bright full-spectrum grow lights.

If you want to grow your Euphorbia trigona in a greenhouse, you should probably place it in direct sunlight at first, and only move to indirect sunlight if the plant shows signs of heat stress.

Watering

Watering-Euphorbia-Trigona

Most African milk trees have a shallow root system that needs sandy, well-drained soil to thrive.

They still need plenty of water, but you need to be sure to provide drainage holes for container plants or they’re likely to develop root rot.

It’s also important not to let containers sit in excess water since that can prevent the soil from drying as completely as the plants require.

Many people think that because African milk trees are cactus plants (some even call them candelabra cactus), they don’t need much water, which is far from the truth.

Like other succulents, your African milk tree needs a lot of water to thrive. They will even start to droop and feel soft when they don’t have enough water.

The key is to provide plenty of water but then to allow the soil to dry completely between waterings. Ideally, with a good soil mix and the right climate, wet soil will dry in just a few days.

However, because this is a plant that’s used to a dry or arid climate, it’s better to wait a couple of extra days between waterings if you aren’t sure whether your plant is ready.

If you water too soon, or before the soil is dry, your plant is at risk of root rot.

On the other hand, if you water too little, leaf drop may occur. However, giving it some water should solve this issue.

Soil

Soil-For-Euphorbia-Trigona

The best soil for an African milk tree is soil that is designed for cactus and succulents.

If you decide to use a general potting mix, consider adding soil amendments like coarse sand or perlite to make the mix drain water better.

For African milk trees planted outdoors, consider adding sand to loamy or clay soils to help improve drainage.

Plants may also benefit from nearby drainage channels or planting on a slight slope so water runs downhill and away from the African milk tree’s roots.

If you do plant indoors, plant them in this premixed, fast-draining potting soil. It’s a little pricier than your general potting soil, but it’s worth it because it has all the soil amendments and additives to make it a very well-draining soil. Our indoor houseplants all thrive in it.

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Fertilizer

Euphorbia trigona plants do well with minimal fertilizer feeding.

You can get away with only feeding African milk tree plants once every few months, or whenever you notice that the plant is starting to grow faster.

Since this is not a particularly picky succulent, you can use standard balanced fertilizer with a 10/10/10 nutrient profile.

However, some growers prefer a succulent or cactus-specific fertilizer. Especially if they are planting outside and live in an area that doesn’t have a lot of natural succulent and cactus species.

Pests

Healthy African milk tree plants don’t attract a lot of insects because the toxins in their sap help make them more resistant to some of the more common plant pests.

However, mealybugs can be a problem and are usually easily identified by the thin silk they leave behind on the plant’s leaves and stems.

Mealybugs can usually be removed with a damp washcloth or paper towel with a little dish soap, by spraying the plants with water (and drying them), or by using rubbing alcohol.

If you are looking for a natural insecticide, try Neem oil. We normally use this particular Neem oil spray. It’s nothing fancy, but it’s pre-mixed and we’ve used it on our pest infestations and works for us.

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Plant Diseases

The African milk tree is vulnerable to fungal diseases, including root rot, and can also get cork disease.

One of the most common diseases affecting milk trees is root rot. The disease results in the decay of the root system and leads to death.

Infected trees usually die within a few years. There is no cure for this disease, but diseased parts of trees can be cut away and a fungicide can be put on them.

Cork disease is more treatable than root rot, but still requires owners to cut off any infected portions of the plant to prevent the spread of the disease. The first symptoms of cork disease are wilting and dead branches.

As the infection progresses, portions of the plant look like cork. The tree can eventually die from the infection.

There is no cure for cork disease, but it can be treated by pruning out infected branches and treating the tree with a fungicide.

Repotting

Repotting-Euphorbia-Trigona

Your African milk tree shouldn’t need frequent repotting. They do best when left alone; these plants can go as long as a year or two between repottings.

A sign that your African milk tree needs repotting is when it seems to be growing well and then suddenly stops growing. That may be a sign that it needs a new, larger plant pot.

Your African milk tree will likely need a larger plant pot at least once every 6 to 12 inches of vertical stem growth (don’t count leaf height).

Other than growing further, another reason for repotting is that repotting will help avoid soil compacting.

Compacted soil will prevent drainage, so when you repot your African milk tree, add some coarse sand to your soil.

Plus, due to African milk tree’s shallow roots, repotting will help aerate and loosen the soil.

Lastly, as for the new pot or container, look for porous pots that help absorb excess water and aid in drying, like a clay pot.

Avoid glazed or glassy pots that hold water and don’t promote air flow.

Propagation

Propagating-Euphorbia-Trigona

The main method of propagating African milk trees is by stem cuttings from a parent plant.

Use a knife or sharp pruning shears to cut a section of stem that’s relatively young; ideally no more than two years old.

Avoid using dull scissors and pruning shears because they won’t provide an even cut and can crush and damage the step instead of slicing it.

Don’t be concerned if the plants excrete a lot of white sap when cut. That’s normal, and a sign that your African milk tree is healthy.

Please note that the milky white latex sap produced by African milk tree is toxic.

Make sure you have protective gloves at least, and you should work in a clean and protected work area.

People who are concerned about getting the sap on their faces should wear eye protection.

Plant owners who are allergic to latex may need to take special precautions to propagate this plant, or even to care for nicks and cuts in the stems.

You can run your cuttings under a tap of cold water until the sap stops flowing. This won’t hurt them and will make the cuttings a little safer to handle.

Next, you’ll want to let the new cuttings rest for a few days, maybe up to a full week, in a cool, dry environment.

That will allow a callus to form over the cut, which helps protect the plant when you’re ready to put it in the soil.

Plant the cutting so that roughly an inch is in the soil, and keep the soil moist until the cutting starts to establish its own roots and grow as normal.

Pruning

Prune your Euphorbia trigona only when it starts to get top heavy and unbalanced.

Pruning does not promote healthier growth, but it can stop container-grown plants from toppling over if they get too unbalanced.

As with propagating, take precautions when pruning your African milk tree.

Protect your hands and eyes, and use a sharp knife or sharp pruning shears to remove any unwanted stems or sections of the plant. Avoid pruning more than 10% of the plant at a time.

If you’re looking for a pair of pruning shears, we really like these pruning shears. They are not too expensive and they seem to never dull. Plus, they are easy on the hands.

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FAQ

How Big Does the African Milk Tree Get?

Some African milk tree plants have been observed to reach a height of 15 feet in the wild! When planted outdoors, a Euphorbia trigona cactus can grow to reach between 7 and 9 feet tall. When cultivated indoors, they average 2 to 4 feet tall.

Is the African Milk Tree Poisonous?

African milk tree plants are very poisonous. The milky latex sap produced is the poisonous feature of this plant. Eating this will be very toxic, can be lethal, and can cause serious skin rashes. It is best not to grow an African milk tree plant around pets or young children.

How Often Should I Water My African Milk Tree?

You should water African milk tree plants once a week. Check the soil moisture once a week and water when the top part of the soil feels dry to the touch. Water evenly and thoroughly from the top layer of soil and allow it to soak in all the way until it drains out the bottom of the pot. When the weather gets warmer, it is a good time to increase watering because the plant is actively growing.

Why Is My African Milk Tree Turning White?

The African milk tree turning white is likely due to the stress on the plant. Stress could stem from transitioning from indoors to outdoors or moving a plant from a full-sun area to one that has limited sunlight. Another reason why your African milk tree plant is turning white is overwatering. Overwatering can also cause other issues, like root rot.

Why Is My African Milk Tree Turning Purple?

If your African milk tree is healthy and is turning purple, it is probably because you have a variety called Euphorbia trigona ‘Rubra’. The Rubra African milk tree creates a purplish-blue hue when it gets an increased amount of sunlight.

Conclusion

Euphorbia trigona is a low-maintenance plant for beginners. These plants are fantastic for landscaping or can be a great addition to houseplants for home decor.

Just make sure to keep them away from pets and young children because, when cut into, they can excrete milky sap that is poisonous.

Other Euphorbia Plants

The Euphorbia plant genus comprises more than 2,000 species of plants. We can only cover so many! But below are some of our favorites to check out.

Euphorbia Milii: Famously known as the “Crown of Thorns”, the flowers of this plant bloom are bright and deep red. They are thought to have been first planted in the Middle East. Also, legend says that Jesus Christ wore a crown of thorns made from this very plant. Hence, some refer to it as the Christ Plant or Christ Thorn. It has many varieties and can be planted indoors or outdoors in warm climates.

Euphorbia Hypericifolia Inneuphdia: The Diamond Frost Euphorbia is a very hardy plant that can endure just about everything you can throw at it. It is really simple to care for, and the gorgeous small white flowers it produces do not require any kind of deadheading. It can be cultivated on its own as a standalone plant or used as a cut flower in floral arrangements. Either way, it will provide texture and curb appeal to whatever front yard it is planted in.

Euphorbia Leucodendron: Typically referred to as the Cat Tails Euphorbia Plant, the Euphorbia leucodendron is a succulent shrub with spineless branches, that can develop into a small tree under optimal conditions. It is an excellent landscape plant. It is native to the subtropical region of Madagascar, where it can grow up to 3 to 4 meters tall. It is not the same plant as Euphorbia tirucalli because its stems are much thinner and have fewer branches.

References

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  • Bhangu, P. et al. (2022). Succulence. Department of Biological Sciences, California State University, Stanislaus. URL: https://www.csustan.edu/biology/stan-state-greenhouse/desert-plants-storing-and-protecting-water
  • University of Arizona Campus Arboretum. (n.d.). Euphorbia Trigona. College of Agriculture and Life Sciences, The University of Arizona. URL: https://apps.cals.arizona.edu/arboretum/taxon.aspx?id=1117.
  • University of Washington Botanic Gardens. (n.d.). Propagating Euphorbia Trigona From Cuttings. Plant Answer Line Question, Elisabeth C. Miller Library, University of Washington Botanic Gardens. URL: https://depts.washington.edu/hortlib/pal/propagating-euphorbia-trigona-from-cuttings/
  • About/mentions: Euphorbia trigona, Euphorbia, succulent

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