Euphorbia submamillaris

Euphorbia submamillaris is a small succulent, a plant that stores water. It belongs to the spurge family, Euphorbiaceae. Kew lists its native range as South Africa’s Cape Province. Kew also places it in a subtropical climate. LLIFLE is less sure where it comes from. It reports plants known only from gardens or pots. It suggests they may come from a hybrid cross. The first description used dried plant parts of unknown origin. Plants grown under this name can vary a lot. This holds true even for seedlings.

This small, woody-based shrub lives for more than one year. It forms low clumps with many branches. It grows about 0.66 feet [0.2 metres] tall. Its upright stems form a tight clump shaped like a column. Branches measure about 0.05–0.08 feet [0.015–0.025 metres] across. Some reach 0.13 feet [0.04 metres] across. Each branch has seven to ten ribs. Deep grooves lie between the ribs. Low bumps line each rib, with crosswise grooves between bumps. Full sun can turn the stems chalk-white.

Tiny green leaves grow at the tips of new branches. They are fleshy and shaped like a lance. These leaves soon fall off. What look like spines are sterile peduncles, or flower stalks. Each bears three or four small bracts. Small wine-red flower structures grow in groups at branch tips. These structures are called cyathia. Male and female cyathia grow on separate plants. Each cyathium measures about 0.016 feet [0.005 metres] across. LLIFLE reports lots of blooms but gives no bloom season. It does not describe the fruit or seeds.

This plant grows well in pots and needs little expert care. Use a mineral potting mix that drains very well. LLIFLE says it accepts a range of soils. Give it ample light to keep its tight shape. Full sun brings out the best stem colour. Less sun can lead to faster, looser growth. That growth may need support. Water and feed it while it grows. Keep it fully dry during its winter rest, around 4°C. The source gives no tested frost limit.

Growers can raise new plants from seed, branches, or offsets. Let cut surfaces heal for about a week before planting. Fresh cuts can rot if planted before they heal. Seeds may sprout within one to three weeks. Damaged stems give off poisonous white latex sap. This sap can irritate skin. Keep it away from eyes and mouth. Take care when taking cuttings or removing offsets.