Scientific Name — Euphorbia inermis

Common Name(s) — Medusa’s Head or Green Crown

Plant Family — Euphorbiaceae

Background

Euphorbia inermis is native to the eastern Cape of South Africa. It is a small geophytic species, both a caudiciform and medusoid Euphorbia. It has many branches that radiate from a central stem, which resembles a spiral when viewed from above.

Growth Requirements

Sun

Euphorbia plants do best in full sun, at least 5 to 8 hours a day. Avoid intense afternoon sun. Grow outdoors in light shade or indoors in a sunny window with southern exposure and direct sun.

Temperature/ Humidity 

Euphorbia inermis prefers warm temperatures in the 70s and 80s. It can become stressed if left in extreme temperatures or intense sun.

Water

Native to arid and subtropical climates, Euphorbia inermis is a drought-tolerant plant. Their soil should be allowed to dry out entirely before watering thoroughly.

Water less in the dormant months when it's resting. About the only way to kill this plant is by overwatering, especially in winter.

Soil/Roots

Euphorbia inermis grows best in a fast-draining soil mix. Use cacti or succulent soil, or amend potting soil with sand or pumice up to 50% to improve drainage.

The caudex is a tuberous root stock which is an underground water-storage organ, so it is very resistant to drought.

Flowering

In optimal conditions, the plant will flower in spring and summer. Each branch crown will be covered with fragrant, pure white or yellow flowers.

Fertilization

These plants do not require fertilizer, though it can be added to give container-grown plants a boost or to supplement poor soil. Apply a water-soluble, balanced fertilizer monthly, diluted at half strength. 

Propagation

You can propagate Euphorbia by seed or branch cuttings. 

• Sow freshly harvested seeds in a gritty, well-drained mix

• Keep soil moist

• Provide ample humidity to encourage germination and seedling growth

If you propagate by cutting, let the cut callus for a couple of weeks before planting.

Health

Diseases and Pests

These plants are quite resistant to pests and diseases. Root rot can become a problem if the plant is overwatered, and it will quickly kill the plant. Plants weakened by root rot are more susceptible to common pests, so always err on the side of underwatering.

Maintenance (pruning, legginess, repotting)

Little maintenance is required to grow these plants. Pruning is only necessary if parts of the plant are unhealthy or damaged. 

Toxicity 

All Euphorbia plants contain a poisonous sap that is very toxic if ingested and highly irritating to the skin. Keep out of reach of pets and children. Wear gloves and take great care when handling this plant.

FAQs

Can I keep my Euphorbia inermis outdoors year-round?

If you live in a warm, frost-free climate, then you can. In cooler regions, if you want to enjoy Euphorbia inermis outdoors in warmer weather, it’s best to plant it in a container. That way, you can bring it indoors to a sunny spot before it is exposed to prolonged cold or harsh precipitation. 

How do I know if I’m overwatering my Euphorbia inermis?

If the stems or caudex become yellow or soft, that’s a sign of overwatering. Always let the soil dry completely between waterings.

Why does the base of my Euphorbia inermis look swollen?

Don’t panic! That base, or caudex, appears swollen by design. This is where your plant stores water and nutrients so it can survive during periods of drought.