Euphorbia trigona

Growing in Pots, Balconies & Indoors

Euphorbia trigona (African milk tree) is an upright, candelabra-like succulent reaching 0.3-3 m (1-10 ft). The grower does not list it as a houseplant, though it is one of the most popular indoor succulents worldwide – the key indoors is a very bright, sunny position.

Quick Details

• Container Size: A snug, heavy-based pot, 15-30 cm; these succulents like being a little tight and can get top-heavy
• Indoor Suitability: Grower says not a houseplant; in practice a well-known indoor succulent for a very bright spot
• Best Spot: Full sun to part shade
• Soil & Drainage: Gritty, free-draining cactus/succulent mix
• Watering in Pots: Sparse – let the mix dry fully between waterings

Indoors & On the Windowsill

• Grower’s view: He does not rate it as a houseplant – it wants strong light and can stretch and weaken in an average room.
• In practice indoors: It is widely and successfully grown indoors as a bright-light succulent; give it your sunniest window, use a heavy pot as it becomes top-heavy, and turn it for even growth.
• Overwintering: Tender – in cold climates keep it frost-free indoors and almost dry through the low-light season.
• Safety: All Euphorbias bleed a milky latex sap that irritates skin and eyes and is toxic if eaten – keep it away from children and pets and wear gloves when pruning.

On a Balcony or Patio

• Light & wind: Give it the brightest spot the balcony offers; shelter exposed plants from strong wind and stake any tall or top-heavy growth. Walls and paving reflect heat, so pots dry quickly – check moisture often in warm weather.
• Practicalities: A filled pot is heavy once watered, so make sure the balcony can take the weight and stand it where drainage runoff will not be a nuisance.

Choosing the Pot, Soil & Long-Term Care

• Pot & drainage: 15-30 cm, in a heavy-based pot to stop it toppling with strong drainage holes; skip a standing water saucer so the roots never sit wet. Terracotta breathes and dries fast, while glazed or plastic pots hold moisture longer.
• Potting mix: A gritty, free-draining cactus and succulent mix – loam or coir cut with plenty of coarse sand, grit or perlite.
• Watering: Water sparingly and let the mix dry out completely between waterings – in a pot, overwatering is the fastest way to rot the roots.
• Feeding: Potted plants exhaust their soil faster because nutrients leach out with every watering – feed lightly but regularly through the growing season.
• Repotting: Refresh the mix or pot up about every couple of years, teasing out and lightly trimming the roots of established plants.

Bloom & Flower Guide

Quick Details

• Bloom Season: Spring, when it flowers at all
• Flower Appearance: Small yellow-green flowers with five segments
• Edibility: Not edible – the plant is toxic and its abundant milky sap is a notable skin and eye irritant

Detailed Blooming Overview

Grown mainly for its tall, three-sided green stems, the African milk tree rarely flowers in cultivation. When it does, in spring, the small blooms are yellow-green. Its abundant milky sap is a notable irritant – hence the common name.

Flower Characteristics

• Small, yellow-green flowers with five segments.
• Produced only occasionally on plants grown indoors.

Bloom Care & Thinning

• Handling: Wear gloves – the copious sap is a skin and eye irritant.
• Position: Bright light gives the best chance of flowering.