Euphorbia trigona ‘Rubra’ (African Milk Tree)

Common Name: “African Milk Tree”; “Cathedral Cactus”

Note: Despite some Common Name Confusion, Euphorbia trigona ‘Rubra’ is not a cactus, nor a tree.

Scientific Classification:
Order: Malpighiales
Family: Euphorbiaceae
Sub-Family: Euphorbioideae
Genus: Euphorbia
Species: E. trigona
Cultivar: ‘Rufra’

Note: Euphorbia trigona ‘Rubra’ is the red form of Euphorbia trigona, which is all green.

Native To: West Africa

Growing Specs:

  • Appearance: Vertical, upright growth that reaches up to 9′ tall. The stem is erect with light green V-shaped mottled variegation. There is a red tinge to the edges and top, and red leaves grow off the stem between the thorns. The tip of the plant tapers off slowly in growth. There are small offshoots that branch off from the main stalk, which match the size of the rest of the plant in time.
  • Flowering: The flowers are white to light yellow, which appear in spring/summer.
  • Hardiness: Hardy to 30 degrees F.

Care Requirements: African Milk Tree is best inside with bright light. Like most succulents, it requires well-draining soil that dries out between waterings, such as this succulent-cactus mix. It doesn’t need watered often. Water about once or twice per month, but in the summer it can get weekly waterings (as long it dries out between waterings). It is pretty low maintenance, but to encourage faster growth, fertilize with Maxsea (my favorite houseplant fertilizer) quarterly.

Propagation: The offshoots can be cut off and stuck directly into soil to propagate. The soil must be relatively dry in order to not rot the cutting while it is establishing roots. Only mist the fresh cutting once per week for about one month until resuming a normal watering schedule.

Toxicity: As with all Euphorbias, when a plant gets damaged, it exudes a thick white milky sap known as latex. This latex is poisonous and particularly dangerous for the eyes, skin and mucous membranes. Therefore, it can be poisonous to pets if ingested. Check out my Pet Safety Guide for more information.

Xylem Rising’s Observations: Euphorbias are extremely slow growing plants, so don’t worry if you barely see any new growth on it at first. You may not notice it getting taller for quite a while (even though it is, but at a snail’s pace), but you will notice the small offshoots that branch off. This plant can get top-heavy, and it has a small root structure, so it may need to be staked up for support. I’ve had the same plant in the same pot for almost 2 years now. Every time I check it for transplanting, it doesn’t need it. If it gets punctured, toxic white sap will leak out. Got milk?



All photo rights belong to Cristie R. Kiley. Please ask permission before taking.

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2 Comments on “Euphorbia trigona ‘Rubra’ (African Milk Tree)

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