Euphorbia aeruginosa

Botanical Name — Euphorbia aeruginosa

Common Name — Miniature Saguaro

Plant Family — Euphorbiaceae

Background

Euphorbia aeruginosa is a dwarf, spiny shrubbing plant from South Africa, where it grows in gravelly rock crevices. Bluish-gray leafless branches are covered in rows of vicious-looking spikes. But come late winter or early spring, watch this metal plant transition to easy listening as its branch tips blossom with delicate yellow flowers.

Growth Requirements

Sun

• Euphorbia aeruginosa do best with a few hours of direct sun in the morning or late afternoon. Filtered light through a sheer curtain (partial shade) during the sun’s peak hours will keep this plant from bleaching. Avoid intense afternoon sun. Grow outdoors in light shade or indoors in a sunny window with southern exposure and direct sun. 

Temperature/ Humidity 

• Euphorbia aeruginosa prefer warm temperatures in the 70s and 80s. It can become stressed if left in conditions of extreme temperatures or intense sun. 
• These plants are not cold hardy. If grown outdoors migrate these plants to a sunny spot indoors when night time temperatures drop below 55 ºF. 

Water

• Native to arid and sub-tropical climates, Euphorbia aeruginosa are drought tolerant plants. Their soil should be allowed to dry out entirely before watering thoroughly.

Soil/Roots

• These plants prefer a sandy, sharply draining mix. Cacti or succulent potting mix is great. You can amend a regular potting soil with sand or pumice up to 50% to improve grittiness and drainage. 
• Euphorbia have very shallow root systems. Mature plants can be quite top heavy. Consider adding a layer top dressing such as lava rocks to cover the soil and provide extra weight to prevent the plant from toppling over, or using a stake to keep the plant upright. 

Flowering

• These plants produce small yellow flowers at their branch tips during late winter or early spring. 

Fertilization

• Euphorbia aeruginosa 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

• Euphorbia aeruginosa can be propagated from stem cuttings. Take great care when cutting these plants as they contain a sap that can be highly irritant if contacted with skin. 
• Allow cuttings to callous for several days before dusting with rooting hormone and placing in soil.

Health

Diseases

• Euphorbia aeruginosa are not prone to pests. Though not super common, they are more likely to fall victim to bacterial or fungal infections. Look out for unusual spotting on stems and remove any affected parts of the plant. If the infection has not spread, the affected area can be cut away and the rest of the plant can be salvaged. Infections that have spread throughout the plant are more difficult to treat and the entire plant may need to be destroyed. 
• Root rot can also be a concern and is triggered by overwatering. 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. 
• These plants are fairly rapid growers. Repot to a pot 2 inches wider every two or three years.

Toxicity

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