for mashua, search for "Ken Aslet Tropaeolum tuberosum". I don't have a good one for ulluco. there was a gal on etsy selling both a couple of years ago, though her mashua wasn't day-neutral. I don't know if she's still selling them. I ordered a dormant tuber of Ken Aslet mashua a while back from I don't remember where, but it didn't ever sprout. definitely let us know if you find some.
I've looked high and low for mashua and ulluco sources (I spent an entire day once trying to track Mashua down), and have been able to find a few places, though they're hard to find online.
Mashua I eventually found at the Occidental Arts and Ecology Center in Occidental (in Nothern California). They don't ship tubers though, but if you live near there or happen to be by there, that's a good spot. They also grow ulluco there. Another place to get tubers online is through Seed Savers Exchange (you need to sign up for a membership and then you'll see listings for Mashua and also Ulluco - yacon as well). I got some mashua tubers from a guy in Belgium who's growing mashua, ulluco, oca, and a bunch of other cool alternative staple crops. I'm not sure what the climate is where you're at, but I've heard ulluco doesn't do so well in the Northwest (it might do well in California) and that most tubers have disease issues, so I haven't attempted growing them.
I've found one source in the U.S. for Ken Aslet mashua tubers (the trouble with mashua is it won't form tubers until after the autumn equinox, but the Ken Aslet variety will form tubers before then and you'll get a lot more tubers from it) at www.mzbulb.com. Unfortunately, they're sold out right now, and I'm kicking myself for not buying them when they were available. Hopefully, they'll be available in the coming months sometime. If you're in the UK or Europe, you should have no problem tracking some down. They're a common ornamental plant there.
I forgot to put in the last post - I can send you a couple tubers of mashua if you'd like. They're not day neutral, so they'll only produce after the autumn equinox like oca, but they're really productive. I got five pounds of tubers off of one plant. Send me a message if you're interested.
I realize that this is an old thread, but, several growers currently offer both.
Strictly Medicinal Nichols Nursery
Oikos Tree Crops
One Green World
I've seen listings for both on EBay, Amazon, Etsy, Bonanza, and, several other markets. Some West Coast Farmers Markets carry them, or, at least potted starts.
I hope this helps.
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