African Milk Tree

OFFICIAL NAME

Euphorbia trigona 'Rubra'

ALSO KNOWN AS

African Milk Bush, Cathedral Cactus, Abyssinian Euphorbia, High Chaparral, Friendship Cactus

ORIGINS & CLIMATE

West Africa | Tropical Savannah

ABOUT THE
PLANT

One of the most whimsical plants we've encountered. The central stem and clusters of "arms" create a tree-like look, while each stem is studded with rows of leaves that stick out and remind us of an aquatic creature and/or alien. This particular variety is also accented with a tinge of red!

HOW MANY GREEN THUMBS?

easy going, drought tolerant, direct, mid-size, upright, compact, tabletop, floor, cactus or succulent, tropical, color, bushy or dense

HMP PLANT PICK

African Milk Tree

The basics

Water Needs

Allow the top half of soil to dry completely between thorough waterings. Reduce frequency as needed in winter or in lower light conditions.

Water

Preferred Light

Primarily plenty of bright, indirect light with a few hours of direct light is ideal for a happy, thriving plant.

Light

Humidity Needs

While not at all bothered about high humidity, your African Milk Tree will appreciate the occasional misting, which helps remove dust from their leaves.

Humidity

Ambient Temperature

Adaptable to average indoor temperatures, but generally prefers the warmer side and may complain when exposed to cold drafts or dry heat from vents.

Temperature

Toxic or Not?

African Milk Trees are mildly toxic to pets and humans. Ingestion will cause mouth and stomach irritation and possible vomiting. Some people experience skin irritation when handling the sap.

Toxicity

Size Potential

Indoors, this plant can grow up to around 4 ft tall with a 1-2 ft spread (when mature and with enough light)!

Size

Overall Look

Resembling an archetypal cactus with a central stem that branches off into dense clusters of "arms," creating something of a tree-like appearance. Each stem has serrated edges that are accented with a thorn and a small leaf. Works best on a tabletop for smaller specimens and on the floor or a plant stand for a larger one.

Format

Leaf Look

Marching along the serrated edges of the stems, these petite leaves are generally a vibrant shade of green tinged with a bit of deep ruby red. But they can also turn entirely red depending on how much light they get. The contrast between green stem and red leaves makes a striking statement.

Leaf Shape

Pro Tip

Your African Milk Tree can eventually get a bit top heavy. You may need to support the stems with stakes to keep them upright.

Pro Tip

Did You Know?

While an African Milk Tree certainly looks like a classic cactus, it is actually classified as a stem succulent Euphorbia. Unlike a true cactus, Euphorbia have leaves and thorns rather than areoles and spines (modified leaves). Euphorbia are also distinct in that they produce a white, latex sap (where the "milk" part of this plant's name likely originates).

Fun Fact

Water

|

Allow half of soil to dry out before watering again.

Water Needs

Allow the top half of soil to dry completely between thorough waterings. Reduce frequency as needed in winter or in lower light conditions.

Light

|

Bright, indirect to direct light.

Preferred Light

Primarily plenty of bright, indirect light with a few hours of direct light is ideal for a happy, thriving plant.

Humidity

|

Not too concerned by humidity levels.

Humidity Needs

While not at all bothered about high humidity, your African Milk Tree will appreciate the occasional misting, which helps remove dust from their leaves.

Temperature

|

Can adapt, but doesn't like sudden change.

Ambient Temperature

Adaptable to average indoor temperatures, but generally prefers the warmer side and may complain when exposed to cold drafts or dry heat from vents.

Toxicity

|

Mildly toxic to humans and pets if ingested.

Toxic or Not?

African Milk Trees are mildly toxic to pets and humans. Ingestion will cause mouth and stomach irritation and possible vomiting. Some people experience skin irritation when handling the sap.

Size

|

An in-betweener. Not too big, not too small.

Size Potential

Indoors, this plant can grow up to around 4 ft tall with a 1-2 ft spread (when mature and with enough light)!

Format

|

A central upright stem with multiple branches or "arms".

Overall Look

Resembling an archetypal cactus with a central stem that branches off into dense clusters of "arms," creating something of a tree-like appearance. Each stem has serrated edges that are accented with a thorn and a small leaf. Works best on a tabletop for smaller specimens and on the floor or a plant stand for a larger one.

Leaf Shape

|

Perky little leaves with a teardrop shape.

Leaf Look

Marching along the serrated edges of the stems, these petite leaves are generally a vibrant shade of green tinged with a bit of deep ruby red. But they can also turn entirely red depending on how much light they get. The contrast between green stem and red leaves makes a striking statement.

Pro Tip

|

You may need to support the stems with stakes.

Pro Tip

Your African Milk Tree can eventually get a bit top heavy. You may need to support the stems with stakes to keep them upright.

Fun Fact

|

Not officially a cactus.

Did You Know?

While an African Milk Tree certainly looks like a classic cactus, it is actually classified as a stem succulent Euphorbia. Unlike a true cactus, Euphorbia have leaves and thorns rather than areoles and spines (modified leaves). Euphorbia are also distinct in that they produce a white, latex sap (where the "milk" part of this plant's name likely originates).

Beyond The Basics

Soil & Potting

Thrives in an airy, light, fast-draining potting mix—you can use a good quality potting mix labeled for succulents/cactus or supplement a standard indoor mix with an equal quantity of pumice or horticultural grit. Ensure the pot has the appropriate drainage and don't forget to pour out any excess water collected in the drainage tray or cachepot.

Repotting

Try to repot every 3-4 years in the spring, especially when tending to a younger plant. Increase the pot size by about 2 inches each time or until you're satisfied with the size. It's still important to repot at this stage, but it'll be an exercise of refreshing to soil, keeping the pot size the same, and possibly doing some root trimming to restrict the plant's growth. More on repotting here.

Feeding

If you're not already planning to repot, you can fertilize during the spring and summer months. Once to every two months should be plenty. No fertilizer is necessary during the winter when plant growth naturally slows down. You can try a balanced liquid or water-soluble fertilizer—always diluted more than the recommended strength. A cactus and succulent specific feed would also work well. More on using fertilizer here.

Grooming

While no specific pruning is required for this plant, it's always good practice to regularly remove yellowed or dying leaves and any fallen plant debris. Ensure your scissors or pruners are sanitized to avoid spreading disease or pests. More on grooming techniques here.

Propagation

To propagate an African Milk Tree, you can take stem cuttings, around 3 inches long. Rinse or wipe off the milky sap. To lessen the chance of rot, let the cutting callus over first by setting out on a dry surface. You can then pot up in a fast draining potting mix and you should see new buds forming soon! More on propagation techniques here.

Variants

TrOUBlESHOOTING

Why are the leaves on my African Milk Tree mushy and yellow?

Symptom

Leaves are yellowing and soft, particularly around the base.

Cause

The most likely culprit is overwatering and initial signs of root rot. When a plant's roots sit in waterlogged soil for too long, a fungal infection can quickly take over, causing the roots to rot—turning brown and mushy.

Solution

First, ensure that your plant has appropriate drainage (both in terms of a well-draining soil and plenty of drainage holes in the plant's container).

If you think you've caught the overwatering early on, you can simply let the plant dry out more than you have been. Allow the top few inches of soil to dry out before watering again. Continue monitoring and only water when needed. You may also try using chopsticks (or something similar) to poke holes in the soil to help the roots get more oxygen. And finally, you can try to "wick" the excess moisture out of the soil by placing the whole pot (with drainage holes) in a tray or container with dry soil. This new layer of dry soil should soak up some of the excess moisture from the waterlogged areas around your plant's roots.

However, if you suspect a serious case of root rot, you'll definitely need to take a peak at the roots by removing the plant entirely from their container. If there are any black and mushy roots, trim them back completely before repotting with fresh soil in a new or sterilized container.

More on leaf changes here.
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Why are the leaves on my African Milk Tree flat and shriveled?

Symptom

Leaves are flat or shriveled, but not soft or yellowing.

Cause

Wrinkling or shriveling of leaves is often a sign of dehydration from either too much light or not enough water. If accompanied by softness or yellowing, this is more likely a sign of not enough light or too much water.

Solution

The key is a well tuned balance between the amount of light and your frequency of watering. Instead of going by a set schedule, check-in with your plant to see if they need the water or not. You'll want to allow around half the soil to dry out completely before watering again. While this may be on a consistent schedule for some months, as the seasons change, so will the amount of light and therefore your watering schedule must shift.

More on watering here.
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Why is my African Milk Tree soft and yellowing at the base?

Symptom

One or multiple stems feel a bit soft and may be starting to yellow or brown at the base.

Cause

This is a sure sign of persistent overwatering. The root rot has spread and led to stem rot as well.

Solution

You will have to cut back any stems with signs of rot. To avoid further spread, you should also take a peak at the roots by removing the plant entirely from their container. If there are any black and mushy roots, trim them back completely before repotting with fresh soil in a new or sterilized container.

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Why isn't my African Milk Tree growing?

Symptom

Slow or no new growth. Possibly accompanied by pale new growth.

Cause

This is most likely due to insufficient light. African Milk Trees are accustomed to receiving plenty of sunlight. Unlike most houseplants, they can generally withstand multiple hours of direct sun every day, something they'll be craving especially during the winter months.

Solution

Improve the lighting conditions for your African Milk Tree to thrive. These plants prefer plenty of bright, indirect light along with a bit of direct light. Make sure to adjust your watering to accommodate the increased light.

More on lighting here.
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