Cow’s Horn Euphorbia
Euphorbia grandicornis
Other Common Names: Mottled Spurge
.jpeg)
Full sun to bright light
Low; soak and then let dry out completely
Moderate (handle with care!)
Indoors 3–5 ft tall
Details
🪴 Plant Type
Perennial succulent shrub (spurge family, Euphorbiaceae)
🌍 Native Region
Coastal woodlands of South Africa & southern Mozambique
📈 Growth Habit
Upright, branching columns with 3(–5) angled stems and irregular wavy margins
📐 Size
Indoors: Typically 3–5 ft (0.9–1.5 m) tall, 2–3 ft (0.6–0.9 m) wide
Outdoors: Can reach 10 ft+ (3 m+) in frost‑free climates
🌸 Bloom Time
Spring–early summer: clusters of small, yellow‑green cyathia (the spurge “flowers”) appear along stems
Care Requirements
☀️ Light
Full sun is best for compact growth and strongest spine color. Will tolerate bright, indirect light but may become leggy and pale
💧 Water
Deep soak when soil is bone‑dry—then allow 2–4 weeks to dry out again. Overwatering → root rot; underwatering → shriveled stems (though it tolerates drought)
🌍 Soil
Very well‑draining cactus/succulent mix (amend with coarse sand or pumice). Neutral to slightly acidic pH (6.0–7.0)
🌡️ Temperature
Ideal: 65–85°F (18–29°C). Minimum: 50°F (10°C); protect from frost
🧪 Fertilizer
Feed with a low‑nitrogen cactus fertilizer once a month during active growth (spring–summer). Do not fertilize in fall/winter
Additional Information
🌱 Propagation Methods
Stem cuttings: let a cut end callus 3–7 days, then plant in dry, well‑draining mix. Seeds: from cyathia, but slow and uncommon
🐛 Common Problems
Root rot: from overwatering or poor drainage. Sunscald: pale or brown patches if moved too abruptly into intense sun. Pests: mealybugs, scale
🌿 Companion Plants
Other full‑sun succulents & cacti, for example: Golden Barrel Cactus (Echinocactus grusonii), Agave spp., Euphorbia trigona (African Milk Tree)
⚠️ Special Notes
Milky sap is toxic & skin‑irritant—always wear gloves when handling or pruning. Keep clear of high‑traffic areas (those horns really catch you by surprise!). Excellent architectural specimen in a sunny spot or xeriscape