Euphorbia ​grandicornis

Euphorbia grandicornis

Family: Euphorbiaceae
Common Names: cow’s horn, cow’s horn succulent, cow’s horn Euphorbia
Geographic Origin: Euphorbia grandicornis is native to hot, dry, low altitude alluvial soils, usually with well-protected grass. The species occurs in small colonies within KwaZulu-Natal, Swaziland, Mozambique, and Kenya.
Description: The cow’s horn Euphorbia is a multistemmed succulent shrub that forms large bushy growths up to 6 feet tall and wide, often collapsing under its own weight. The green stems are uniquely twisted into triangular segments, covered with jointed, conspicuous spines that resemble a cow’s horns. Although tiny leaves will form between the spines in late summer, they are short-lasting and will dissipate.
Bright yellow cyathia appear in late spring, forming in groups of 3 above the terminal spines on the central segments. The middle flower will be stalkless and male, while the two outermost cyathia will be stalked, bisexual inflorescences. Shortly after flowering, the 3-lobed fruits will appear in rows on the angled ridge of branches, and will ripen to an attractive purple.
Interesting Features:

The purple fruits pop open explosively when ripe.
As with all Euphorbia, toxic white latex will exude from the stems when cut, ranging from mildly irritating to very poisonous. Handle with care to avoid contact dermatitis, eye irritation, or other dangerous effects.

Uses: E. grandicornis has traditionally been used to treat skin irritation, inflammation, snake and scorpion bites, and possesses diterpenoids with anticancer and cytotoxic abilities.

Cultivation and Care:
- Watering: Moderate

Unlike most Euphorbia species, the cow’s horn does not tolerate long periods of drought very well, and should be watered whenever the soil is dry several inches below the surface.
However, never allow to sit in waterlogged soil.

     - Soil Type: E. grandicornis is not particular about soil pH, surviving 6.1-7.8 without detrimental effects. However, ensure that the soil is well-draining, and add fertilizer or organic matter to the hole when planting outside. A monthly half-strength fertilizer should also be used if growing in a container or in poor soil.
     - Lighting: Provide full sun for long periods to encourage flowering and proper growth.
     - Propagation: The cow’s horn succulent can be propagated through semi-hardwood cuttings or seed, although seeds are usually difficult to germinate or even locate. Allow cuttings to fully callous over before planting.
     - Cold tolerance: 25°F, USDA hardiness zones 9b-11
     - Special Accommodations: E. grandicornis is not very frost-hardy, and should be protected from freezing. Additionally, always wear gloves when handling, and goggles when grafting or cutting to avoid irritation from the toxic latex.

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