No experience with it yet. I've been looking for it for a long time. I finally found two sources of it from South Africa:
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https://durandtsheirloomseeds.co.za/product/tsenza-african-potato/
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https://livingseeds.co.za/tsenza.html
The second source (Living Seeds) confirmed (on inquiry) that they ship overseas, and that I should watch the page for availability starting around August... Still nothing, but I'm checking often.
I've read that it's a tough and easy plant, though P.r. is easier, and that it's edible raw or cooked. Yellow flowers, long thin tubers.
I also found another Potato Mint, Plectranthus punctatus subsp. lanatus (allegedly different from the third Potato Mint, P. edulis), at Rare Palm Seeds, and placed an order. Still waiting.
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https://www.rarepalmseeds.com/plectranthus-punctatus-subsp-lanatus