Named "edulis" (edible) because its caudex was traditionally eaten by indigenous peoples. A semi-tuberous member of the Apocynaceae family found across a wide swath of South Africa, it produces slender vining stems carrying glossy, oval leaves from a rough, grey-brown caudex. Lift the caudex above the soil line in cultivation and its sculptural texture and waist-like constrictions take on a quietly artistic quality. Easier to find and grow than its cousin crispa, making it a great introduction to the genus, and its vigorous trailing stems invite playful training along stakes or pot rims. A near-perfect first step into the world of caudex plants.
Native climate
Rainfall is spread fairly evenly across the year. Overall a mild climate.
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
A highly adaptable semi-tuberous species native to a wide range of South Africa, edulis takes anything from bright shade to full sun. In the growing season, give it bright outdoor sun for compact stems and leaves, with 30% shade in peak Japanese summer to prevent leaf scorch. The vining stems sprawl, so a stake or rim to twine on keeps the silhouette tidy. Move to a bright indoor window for winter, out of rain.
Watering
In active growth, water thoroughly after the substrate has fully dried, then let it dry again — that wet-dry rhythm fattens the caudex. Prolonged rain causes rot, so shelter under eaves. As autumn leaves drop, taper to dormancy; 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 and reduces rot.
Fertilizer & Supplements
A small amount of slow-release during active growth, plus a monthly dilute liquid feed (around twice the label dilution). Overfeeding etiolates the vines and leads to rot — prioritize caudex bulk over fast top growth.
Temperature & Overwintering
Optimal 20–32°C with an 8°C winter floor — one of the more robust species in the genus. Cold triggers the vines to drop leaves and go dormant; taper water as leaves yellow, then overwinter dry on a bright indoor window, out of rain.
Starting from Seed
Where to source seeds
links go directly to the product page; the rest are scientific-name searches. Stock fluctuates — verify availability on the destination site.
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. Anything still floating is likely past its prime.
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 25–30°C. Expect germination in 10–21 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 vines can get out of hand; prune as needed.
