Euphorbia trigona
(African milk weed)

Preferred Scientific Name

• Euphorbia trigona Mill.

Preferred Common Name

• African milk weed

Other Scientific Names

• Euphorbia hermentiana LEM.
• Hermentiana triangularis

International Common Names

• English: African milk tree; cathedral cactus; high chaparall
• Spanish: cactus candelabro; candelabra

Local Common Names

• Cuba: corona de la reina
• India: triangular Spurge

EPPO code

• EPHTG (Euphorbia trigona)

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Dicotyledonae
•                     Order: Euphorbiales
•                         Family: Euphorbiaceae
•                             Genus: Euphorbia
•                                 Species: Euphorbia trigona

The Euphorbiaceae is a pantropical family, comprising 218 genera and 6745 species (Stevens, 2016). Members of this family are mostly monoecious herbs, shrubs and trees, sometimes succulent and cactus-like plants with xerophytic adaptations (Esser, 2009; Stevens, 2016). The Euphorbiaceae was considered a morphologically well-defined family for a long time, based mostly on their unisex flowers and typical schizocarpous fruits. However, recent molecular studies have resulted in the recognition of several, mostly small families (i.e., Peraceae, Phyllanthaceae, Picrodendraceae, Putranjivaceae). In the most recent circumscription, Euphorbiaceae is defined as clearly monophyletic (Esser, 2009). The genus Euphorbia is among the largest genera of angiosperms, with about 2420 species with remarkably diverse growth forms – such as annual to perennial herbs, thorny/spiny stem or succulents to cactus-like and trees (Horn et al., 2012; Stevens, 2016). Euphorbia trigona is possibly of hybrid origin (PROTA, 2016). There is also an attractive cultivar (Euphorbia trigona cv. Royal Red) with purplish-red stems and leaves.

The following description is adapted from India Biodiversity Portal (2016):

Succulent shrubs or trees, latex milky, branchlets 3-angled, spines 3 mm, divergent, cauducous. Leaves to 2.5 mm, ovate, cauducous. Cyathia solitary or in groups, bracts paired to 3.5 x 4 mm, ovate, obtuse, dentate, glands 5 to 2.2 mm, bracteoles approximately 2.5 mm, obovate, apex fringed; stamens numerous, filaments jointed, 2.6 mm; female flowers erect, ovary about 3.7 mm across, 3-celled, style 3, ovule 1. Capsule to 7 mm, 3-lobed, 3.5 mm, obovoid.

Euphorbia trigona has been widely commercialized and introduced into many countries to be used as ornamental, hedge and potted plant (Riina and Berry, 2016; USDA-ARS, 2016). However, little is known about the history of introduction of this species. It is commonly planted as a ritual plant and as a hedge and ornamental near villages, especially in tropical Africa. In India, it is described as a “common species” in the deciduous forests of Peninsular India (India Biodiversity Portal, 2016). In Cuba this species was introduced as an ornamental and is now becoming invasive (Oviedo et al., 2012).

Soil drainage

• free

Soil reaction

• acid
• neutral

Soil texture

• light
• medium

Euphorbia trigona mostly spreads vegetatively by cuttings and stem fragments (PROTA, 2016). Flowers and fruits are rarely produced. This species is primarily moved/introduced into new habitats by humans (Riina and Berry, 2016; PROTA, 2016; USDA-ARS, 2016).

Euphorbia trigona has the potential to displace native vegetation and may form hedge-like barriers in invaded areas. This species has the potential to outcompete native plants for water and nutrients (PROTA, 2016).

The latex of E. trigona is poisonous and caustic for humans, livestock, cats, dogs and wild animals (PROTA, 2016; USDA-ARS, 2016).

• Proved invasive outside its native range
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Tolerant of shade
• Benefits from human association (i.e. it is a human commensal)
• Long lived
• Fast growing
• Reproduces asexually

• Modification of hydrology
• Modification of nutrient regime
• Reduced native biodiversity
• Threat to/ loss of native species

• Causes allergic responses
• Competition - monopolizing resources
• Competition - smothering
• Poisoning
• Rapid growth
• Rooting
• Produces spines, thorns or burrs

• Highly likely to be transported internationally deliberately

Social Benefit

Euphorbia trigona is widely commercialized as an ornamental and potted plant and, due to the presence of spines, it is also used as a fence/hedge plant (USDA-ARS, 2016). In tropical Africa, it is commonly planted as a ritual plant and hedge near villages (PROTA, 2016). In India, the sap from the plant is mixed with the mud from termite mounds and is applied on the blades of new knives and axes to sharpen them. The latex is also used as a fish poison (India Biodiversity, 2016).