A small caudex-forming Apocynaceae (Asclepiadoideae) from grasslands across KwaZulu-Natal, Mpumalanga, Limpopo, Zimbabwe, and Mozambique. A flattened spherical tuber 3–8 cm across — smaller than B. barberae — sits half-buried below ground, sending up short stems and narrow leaves; in summer it produces small dark purple-red star-shaped flowers. The epithet foetidum means "stinking," and the flowers live up to it, drawing flies with a strong putrid scent. The 2017 Bruyns phylogeny merged the entire genus into Ceropegia (accepted name Ceropegia rehmannii), but the trade still uses Brachystelma. Wider in distribution than barberae and easier to find from seed.
Native climate
Rainfall is spread fairly evenly across the year. Overall mild, at high elevation, with a wide temperature range, and cold winters.
A broad-scale picture of the native range. Real growing spots — rock crevices, fog belts — can be milder.
Sources: climate & elevation WorldClim 2.1 (1970–2000) · occurrences GBIF · native range POWO · current weather Open-Meteo
Care
Light & Placement
In its native South African grasslands it grows under strong summer sun. Through the growing season, full direct sun outdoors gives the best caudex thickening and flower production. A 20–30% shade cloth helps through Japan's worst midsummer; raise pots off the ground for airflow. After the leaves die back in autumn, taper water and overwinter on a bright indoor window above 5°C — bone-dry. The tuber rests fully underground in winter.
Watering
In active growth, water deeply once the substrate has dried, then dry it out fully again. The caudex stores water and is rot-prone, so shelter pots from prolonged rain. Once leaves yellow in autumn, taper water and go fully dry through winter, with at most a single light misting per month.
Substrate
Drainage first, inorganic-led. Akadama : Kanuma : pumice = 4:3:3 is reliable. Plant with the top of the caudex slightly visible at the surface to tighten the form and reduce rot risk.
Fertilizer & Supplements
A diluted liquid fertilizer monthly through active growth, or a small pinch of slow-release at repotting. Pushing too hard invites caudex rot.
Temperature & Overwintering
Optimal 22–32°C with a 5°C minimum. Damp soil with cold rots the tuber — keep it bone-dry through winter on a bright indoor window.
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. Persistent floaters are typically a sign of stale stock; seed viability falls off quickly.
Substrate
Use a separate seedling mix that's fine-grained and near-sterile: fine Akadama, fine Kanuma, and vermiculite in 1:1:1 parts. Sterilize beforehand to reduce damping-off.
Sowing method
Sow with no covering, or only the thinnest dusting so the seeds remain partly visible. Space at least 1 cm apart.
Light & temperature
Bright shade, 22–28°C steady. Germination takes 14–30 days.
Watering
Bottom-water with the level 1–2 cm up the pot. For the first 2–3 weeks, prioritize not letting things dry out, then drop the water level gradually.
Fertilizer
No feeding right after germination. Once true leaves emerge, give diluted liquid fertilizer at double dilution, once or twice a month.
From Germination to Repotting
Germination through true leaves
Continue bottom watering, keep strong light off them.
Weaning off bottom watering
Phase out gradually over 1–2 months.
First repotting
In year one or two, once the tuber has reached fingertip size.
Common Pitfalls
Mold & damping-off
- Cause: excess moisture, contamination, poor air flow
- Prevention: sterilize the substrate, refresh the bottom-water, and use a circulation fan
Etiolation
- Cause: insufficient light
- Prevention: move LEDs closer right after germination, or shift the tray to bright shade outdoors
Seeds fail to germinate
- Cause: stale seed, insufficient warmth
- Prevention: source fresh seed from reliable sellers and hold 22–28°C steady on a heat mat
Notes
Open flowers smell of carrion — keep the pot outdoors during bloom. The sap is mildly toxic.
