Euphorbia ritchiei

Kenyan range and habitat of Euphorbia ritchiei

Euphorbia ritchiei is native to Kenya, where it grows in dry shrubland and on stony or rocky slopes.

Rain falls seasonally in its native habitat. It grows on open, fast-draining ground that dries well between wetter periods. These exposed sites are warm and bright.

Caring for Euphorbia ritchiei indoors

• Repotting: Use a pot with enough width for new shoots that spread below the surface. Move to a slightly wider pot when new stems reach the rim.
• Watering: While leaves are growing, water after the potting mix is dry and the pot feels light. If the leaves thin out and growth pauses, water much less often and let the mix stay dry between waterings.
• Light: Bright light with some direct sun suits the leafy stems. Introduce direct sun gradually.
• Potting mix: Use an airy, gritty succulent mix around the fleshy underground base so excess water drains quickly.
• Temperature: A warm room suits it best, with temperatures staying above about 10 °C. In cooler conditions, let the mix stay dry longer.
• Humidity and airflow: Average room humidity is suitable. Keep air moving through the leafy clump after watering.
• Feeding: Give a light dose of succulent fertiliser only while leaves and new shoots are growing.
• Propagation: An established clump can be divided if each piece has healthy roots and at least one stem. Stem cuttings are another option. Let cut surfaces seal and wear gloves and eye protection around the latex.

Problems and solutions for Euphorbia ritchiei

• Leaves fall while the stems remain firm: Leaf drop can follow slower growth, lower light or a change in conditions. Check that the stems and base are firm and make sure the plant is still getting enough light. If growth has slowed, water less often. If it is still growing in weak light, move it closer to a brighter window.
• The fleshy base under the potting mix feels soft or smells sour: Softness or a sour smell from this fleshy base strongly suggests rot after prolonged wetness. Stop watering, unpot the plant and cut away rotten roots and any soft tissue with a clean blade until only firm, healthy tissue remains. Discard the rot, wait for the cuts to seal, then repot the remaining healthy plant.
• New shoots become long, pale and weak: Long, pale and weak new shoots often indicate insufficient light. Move it gradually into a brighter position so later shoots grow shorter and sturdier.
• Cottony pests gather around leaves and raised bumps: Mealybugs can settle around the raised bumps. Isolate the plant, remove visible insects and use a treatment labelled for mealybugs, repeating it only as directed.

Euphorbia ritchiei is toxic to people and pets

• Keep this plant away from children, cats and dogs, and avoid contact with its milky sap.
• The sap contains irritating diterpene esters that can burn the mouth and damage skin or eyes.
• Sap exposure may cause painful irritation, while swallowing plant material can cause vomiting or stomach pain. Contact a veterinarian or medical professional promptly, especially after eye exposure.

How the name Euphorbia ritchiei came about

Euphorbia honours Euphorbus. The epithet ritchiei honours the Scottish naturalist Archibald Thomas Ayres Ritchie.

Carl Linnaeus established the genus Euphorbia in 1753 in Species Plantarum, page 450.

Peter René Oscar Bally first described it as Monadenium ritchiei in 1959 in Candollea, volume 17, page 32. Peter Vincent Bruyns later placed it in Euphorbia as Euphorbia ritchiei in 2006 in Taxon, volume 55, page 415.