A small Othonna from the granite domes of central and northern Namaqualand in South Africa's Northern Cape, where it wedges into shallow rock fissures with little more than a thimbleful of grit beneath it. Authority is Hutch. (Hutchinson, 1917). The epithet euphorbioides — "Euphorbia-like" — captures the trick: a short swollen stem covered in peeling yellow-grey to reddish bark sends out a halo of stiff, spine-tipped stubs that are actually persistent leaf petioles and old flower stalks, not true thorns. Narrow leaves emerge briefly in autumn, small yellow daisy-like flowers open in early summer, and the plant rests bare through summer as a winter-grower. It was added to CITES Appendix III at the request of South Africa in 2022 (CoP19), so seed-grown or nursery-propagated material is the right way to acquire it.
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
In habitat the rainfall is roughly 100–200 mm a year, falling almost entirely in winter, with cool air and coastal fog supplementing the moisture. Plants live in shallow cracks of granite domes under intense sun but cool air. During the autumn-to-spring active season in Japan, give it as much bright outdoor or windowsill light as possible — strong light keeps the spine-like stubs short and the bark dark grey-green. The dangerous season is summer after the rains: shift to bright shade out of direct sun (50–70% shade cloth), raise the pot on a bench, and run a circulation fan. Winter indoors above 5°C on a bright windowsill is straightforward.
Watering
Restart watering in small amounts from September into October as nights cool, then water properly through the leafy season. Through the active season, soak when the substrate has fully dried; never leave water sitting in the saucer. Cut water in April–May once leaves yellow and drop, and keep dry through summer. Watering in summer because the plant looks "too dry" is the single most reliable way to lose it.
Substrate
Drainage first, inorganic-led. Akadama : Kanuma : pumice = 3:3:4, leaning on pumice to dry faster. Habitat is a shallow rock crack, so a shallow pot that dries from the surface down works better than a deep one.
Fertilizer & Supplements
Liquid feed at heavy dilution once a month through the active season, or a pinch of slow-release at repotting. Native soils are extremely poor; pushing fertilizer softens the jointed form and dulls the bark. Nothing through summer.
Temperature & Overwintering
Optimal 15–25°C; minimum around 5°C. When dry the plant tolerates close to 0°C, but damp soil under cold is fatal. Summering is harder than overwintering: tropical nights above 35°C combined with humidity will rot the base. Keep summer on shade, ventilation and complete dryness; an air-conditioned room is a legitimate retreat.
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. Floaters are a sign of stale stock. Seeds are tiny pappus-tipped achenes; viability drops fast with age.
Substrate
A separate seedling mix, fine-grained and near-sterile: fine Akadama, fine Kanuma, and vermiculite in 1:1:1, sterilized with boiling water or a microwave pass. A thin topping of coarse sand anchors the pappus-tipped seed.
Sowing method
Do not cover the seeds. The pappus catches any breeze, so sow indoors in still air on a pre-moistened surface. Thin clumps after germination.
Light & temperature
Bright shade, 15–22°C. As a winter-grower, heating above 25°C actually suppresses germination. September through November is the right window in Japan; germination takes 10 days to about a month.
Watering
Bottom-water 1–2 cm up the pot. Don't let things dry out for the first 2–3 weeks, then drop the level gradually. Avoid cold water; room-temperature is preferable.
Fertilizer
None right after germination. Once true leaves emerge, a heavily diluted liquid feed once or twice a month. Growth is very slow — first-year seedlings reach only a few mm to ~1 cm; the swollen base takes years.
From Germination to Repotting
Germination through true leaves
Continue bottom watering, keep in bright shade.
Weaning off bottom watering
Phase out gradually over 1–2 months.
First repotting
In the second or third year, in autumn, into a shallow pot.
Common Pitfalls
Mold & damping-off
- Cause: excess moisture, contamination, poor airflow
- Prevention: sterilize the substrate, refresh the bottom-water, run a circulation fan
Etiolation
- Cause: insufficient light. The active winter season runs through low-sun months
- Prevention: run an LED close indoors, or move to bright shade outdoors on clear days
Seeds fail to germinate
- Cause: stale seed, temperatures too high
- Prevention: sow as soon as a batch arrives. Skip the heat mat — keep room temperature 15–22°C
Summer stall and rot
- Cause: heat and humidity during summer dormancy, or watering in summer. The single biggest risk for this species
- Prevention: taper water from April–May and go fully dry before the rainy season; through summer hold under shade with airflow in the coolest spot, with an air-conditioned room as a legitimate option
Notes
Listed on CITES Appendix III; check paperwork when importing.
