Scientific Name
Euphorbia polygona Haw.
Common Name(s)
African Milk Barrel
Synonym(s)
Euphorbia polygona var. polygona
Scientific Classification
Family: Euphorbiaceae
Subfamily: Euphorbioideae
Tribe: Euphorbieae
Subtribe: Euphorbiinae
Genus: Euphorbia
Etymology
The specific epithet "polygona" (pronounced "pol-LIG-go-nuh") means "polygons" and refers to the angular, many-ribbed stems of this species.
Origin
Euphorbia polygona is native to South Africa. It occurs on gravelly flats to stony slopes among karroid scrub from Seweweekspoort and Calitzdorp to Makhanda, also known as Grahamstown.
Description
Euphorbia polygona is a much-branched succulent with grey-green stems with obscure tubercles fused vertically into 7 to 20 prominent, wing-like angles. The cylindrical-clavate stems can grow up to 6.6 feet (2m) tall and 6 inches (15 cm) in diameter. The spines can measure up to 1.6 inches (4 cm) in length and arise in the axil of each tubercle, usually in a group of 2 to 5. The tiny leaves are soon deciduous.
Many cyathia appear around the apex of each stem, 1 to 3 on each persistent peduncle in the axil of the tubercle. They can reach a diameter of 0.3 inches (0.7 cm) and have five entire red to dark purple glands. The fruits are densely hairy capsules that contain one seed in each cell, and can grow about 0.25 inches (0.6 cm) in diameter. This species is dioecious, with male and female flowers occurring on different plants.
Varieties and Cultivars of Euphorbia polygona
Hardiness
USDA hardiness zones 9b to 11b: from 25°F (-3.9°C) to 50°F (10°C).
How to Grow and Care
Euphorbias are very easy to care for. These plants require a little pampering to become established, but once they are, they are self-sufficient. In fact, more die from overcare than from neglect. Euphorbias need well-draining soil and ample sunlight. They are not particular about soil pH, but cannot tolerate wet soil. Unlike most succulents, Euphorbia does not handle long periods of drought well. It may need weekly watering during the summer. Water whenever the top several inches of the soil are dry. Water deeply, but avoid letting them sit in wet soil, as this can cause root rot. Add some organic matter or fertilizer to the planting hole. Feed with a half-strength fertilizer monthly if you are growing them in containers or your soil is poor.
These succulents can be grown from seed, but they can be difficult to germinate (or even find). They are usually propagated by cuttings. This can be tricky because of the exuding sap. A rooting hormone is recommended for Euphorbias. They tend to grow problem-free, but a few pests and diseases are to be alert for.
Learn more at How to Grow and Care for Euphorbia.
Links
- Back to genus Euphorbia
- Succupedia: Browse succulents by Scientific Name, Common Name, Genus, Family, USDA Hardiness Zone, Origin, or cacti by Genus
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