A much-loved small Euphorbia of clustering globes covered in countless fine tubercles. Native to the quartz-strewn gravel of the Little Karoo in South Africa's Western Cape, its 3–4 cm spheres offset freely into low, hemispherical colonies. In habitat most of each plant sits buried in the ground, with only the crowns showing at the surface. Tough and quick to form clumps, it's a familiar gateway species. The epithet honors Susanna Muir, and in cultivation it is widely sold under the spelling "suzannae." Its wild range is very small, and as a succulent Euphorbia it is listed on CITES Appendix II. The milky-white sap is mildly caustic, so handle with light care.
Native climate
Rain concentrates in the cool season, with a dry season of roughly 6 months. Overall mild, with a wide temperature range.
* Accurate distribution data is scarce for this species, so these values are taken from the climate near the approximate center of its native range instead.
Sources: climate & elevation WorldClim 2.1 (1970–2000) · occurrences GBIF · native range POWO · current weather Open-Meteo
Care
Light & Placement
From the quartz gravel of the Little Karoo, where it grows in the open or in the half-shade of small bushes, it likes bright light. Give it generous outdoor sun in the growing season to keep the spheres firm and the tubercles sharply defined — too little light flattens the form and discourages flowering. In Japan's peak summer, a light 20–30% shade plus a raised shelf and good airflow prevent scorch and stagnation. Move it to a bright indoor window, out of rain, and keep it on the dry side for winter.
Watering
Because the spheres store water, it needs less than most Euphorbias. In active growth, water thoroughly two or three days after the substrate has dried, then let it dry again — overwatering is the bigger risk, not drought. In winter, mist once or twice a month.
Substrate
Drainage above all, in an inorganic mix. Small-grain Akadama : Kanuma : pumice = 4:3:3 is a reliable baseline. A pinch of slow-release such as Magamp K helps early growth, and a taller pot improves wet-dry cycling.
Fertilizer & Supplements
A small amount of slow-release during active growth, plus a monthly dilute liquid feed (around twice the label dilution). Overfeeding tends to distort the spherical form — grow it slowly and lean for a tight, well-shaped plant.
Temperature & Overwintering
Optimal 20–32°C with a 5°C winter floor. Damp soil at low temperatures is the main risk. From autumn, taper water in stages and overwinter dry on a bright indoor window, out of rain.
Starting from Seed
Where to source seeds
Pre-sowing treatment
Soak seeds for about half a day (overnight) in a mix of a registered seed-treatment fungicide (Benlate or Daconil) and a plant tonic (Menedael; outside Japan, SUPERthrive or a chelated iron / seaweed extract works similarly), each diluted per label. The ones that stay on the surface tend to germinate poorly. Freshness varies with storage, so sow as soon as you can after receiving seed.
Substrate
Use a separate seedling mix that's fine-grained and near-sterile: fine Akadama, fine Kanuma, and vermiculite in equal 1:1:1 parts. Sterilize the mix with boiling water or a quick microwave pass before sowing.
Sowing method
Sow with no covering, or only the thinnest dusting of substrate so the seeds remain partly visible. Space them at least 1 cm apart so they don't clump or overlap on the surface.
Light & temperature
Keep the tray in bright shade at a steady 22–28°C. Expect germination in 7–21 days. Germination depends on seed freshness, but with fresh seed it is reasonably steady.
Watering
Bottom-water with the level 1–2 cm up the pot. For the first 2–3 weeks, prioritize not letting things dry at all, then drop the level in steady stages once the seedlings have come up.
Fertilizer
No feeding right after germination. Once the true leaves emerge, give a heavily diluted liquid fertilizer once or twice a month — go lighter than the label suggests for safety.
From Germination to Repotting
Germination through true leaves
Continue bottom watering and avoid strong light.
Weaning off bottom watering
Wean off gradually over 1–2 months.
First repotting
In year 1 or 2, once the plant becomes root-bound.
Common Pitfalls
Mold & damping-off
- Cause: Excess moisture, contamination
- Prevention: Sterilize substrate, ensure ventilation
Etiolation
- Cause: Insufficient light
- Prevention: Move the LED closer right after germination, or move outdoors to bright shade
Seeds fail to germinate
- Cause: Stale seeds, insufficient temperature
- Prevention: Use fresh seeds and a heat mat
Notes
The latex can irritate if it gets on skin or mucous membranes — take care with hands and eyes.
