African Milk Tree – Euphorbia trigona ‘Rubra’

African Milk Tree “🌵✨ Euphorbia trigona ‘Rubra– The Elegant Red-Edged Succulent
Euphorbia trigona ‘Rubra’, commonly known as the African Milk Tree Rubra or Red African Milk Tree, is a stunning, upright succulent native to Central Africa. It is a cultivar of the green Euphorbia trigona, with distinctive reddish to deep burgundy hues along its vertical stems and leaves.

Known for its candelabra-like form, vibrant colors, and ease of care, this plant is popular in indoor collections and drought-tolerant landscapes. Its rapid, vertical growth and bold architectural shape make it an excellent statement piece for homes, offices, and patios.

🌿 Botanical Overview
Scientific Name: Euphorbia trigona ‘Rubra’

Common Names: African Milk Tree Rubra, Red African Milk Tree, Cathedral Cactus (misleading, as it’s not a true cactus)

Family: Euphorbiaceae

Origin: Central Africa

Growth Habit: Tall, columnar, branching succulent

Size:

Height: Up to 1.5–2.5 meters (5–8 feet) indoors, taller outdoors

Spread: 45–60 cm (18–24 inches)

Stems: Triangular cross-section, upright with spiny ridges

Color: Deep green to burgundy-red stems with contrasting red or purple leaves

Leaves: Small, teardrop-shaped, grow along ridges, and drop seasonally

USDA Hardiness Zones: 9–11

☀️ Sunlight and Temperature Requirements
Sunlight:

Prefers bright, indirect light to full sun

Indoors: Best near a south or west-facing window

Outdoors: Thrives in partial to full sun, with acclimation to avoid sunburn

Temperature:

Optimal range: 18°C to 27°C (65°F to 80°F)

Not frost-tolerant: Protect from temperatures below 10°C (50°F)

Sudden temperature drops or drafts can cause leaf drop

🌞 More light intensifies the rubra (reddish-purple) coloring, while lower light may result in greener stems.

💧 Watering Routine
Growing Season (Spring to Early Fall):

Water when the top 5 cm (2 inches) of soil is dry

Usually every 10–14 days, depending on light and temperature

Always water deeply and let excess water drain completely

Winter Dormancy:

Reduce watering to once every 3–4 weeks

Avoid watering if the plant is in cool conditions and the soil remains moist

💧 Overwatering can cause root rot, the most common issue for this species.

🌱 Soil Requirements
Type:

Requires well-draining soil, typically a cactus or succulent mix

Optional mix:

50% succulent soil

25% coarse sand

25% pumice or perlite

pH: Neutral to slightly acidic (6.0–7.0)

Fast drainage is crucial to avoid moisture accumulation at the roots.

🌾 Fertilizing Schedule
During Active Growth:

Fertilize every 4–6 weeks in spring and summer

Use a diluted, balanced succulent fertilizer (e.g., 10-10-10 or 5-10-10)

During Dormancy:

Do not fertilize in winter

Avoid overfeeding, as excessive nutrients can encourage weak, leggy growth.

✂️ Pruning and Maintenance
Pruning:

Prune to control height, encourage branching, or remove damaged stems

Always wear gloves — the plant exudes a milky sap that is toxic and can irritate skin and eyes

Use sterile, sharp tools

General Maintenance:

Rotate periodically to ensure even growth

Dust off stems gently to allow optimal photosynthesis

🌿 Propagation
By Cuttings:

Cut a healthy stem with a sterile knife or pruner

Allow the cutting to callous for several days to a week

Plant in dry, well-draining soil

Water lightly after the cutting has rooted (typically after 2–3 weeks)

Safety Tip:
The sap is toxic — always handle with gloves and keep away from pets and children.

🐛 Pests and Problems
Common Pests:

Mealybugs

Spider mites

Scale insects

Diseases:

Root rot due to overwatering

Fungal spots if kept in excessive humidity

🛡️ Treat pests with neem oil or insecticidal soap. Ensure good air circulation and avoid stagnant moisture.

🌸 Flowering and Decorative Value
Flowers:

Rarely blooms indoors; if it flowers, blooms are small and insignificant

Grown primarily for its striking coloration and form

Decorative Uses:

Stunning in modern interior decor

Ideal for offices, patios, and succulent gardens

Works well in minimalist or desert-themed arrangements

📸 Its upright growth and vibrant red tones make it a sculptural focal point in any space.

✅ Conclusion
Euphorbia trigona ‘Rubra’ (African Milk Tree Rubra) is a low-maintenance, visually dramatic plant perfect for indoor spaces and warm climates outdoors. Its rapid growth, easy propagation, and bold coloring make it a favorite among succulent enthusiasts.”