Boy are there lots of varieties of yam. Some are edible. Some have edible leaves. Some are only used for medicine.
Below I am chatting about C variety
Dioscorea polystachya
- "Just like Rambo movies, there is Yam A, Yam B and, yes, a Yam C, the
Chinese Wild Yam or the Cinnamon Vine yam, either way we get Yam C,
botanical name, Dioscorea polystachya aka D. oppositifolia (Dye-os-KOH-ree-uh or in Greek thee-oh-skor-REE-uh) [op-os-i-ti-FOH- lee-uh]. Dioscorea oppositifolia only grows in India, where I presume it is eaten. D. polystachya is the one growing in North America. D. oppositifolia is called by some websites D. batata. Regardless, the accepted name for now for the Chinese Yam is Dioscorea polystachya." (quoted from Eattheweeds.com)
I purchased a "ñame"
Yam C variety tuber at Walmart to try. Cutting off the thick, woody
peel left me with a slippery tuber (yams are slippery when cut) that I
cut into pieces and tossed into water so it did not brown. It was
sauteed with a blend of other root vegetables and sausage. The taste was
similar to Irish potato with a very dry and fluffy texture. This
variety would be perfect for mashed "potato" or soup. I am going to try
several varieties of Yam C before making my decision on which to grow in
my garden.
Based on research and not on personal experience (yet) here are my findings...
Do NOT eat raw.
Growing: Probably best to grow in pots where it can be contained.
Yam C can become invasive if aerial tubers are not harvested.
Parts to eat: Underground and aerial tubers.
Propagation: Cut and plant the ends of the yam (with at least two inches), plant aerial tubers, vine cuttings.
Ready to eat: Tubers ready in 4 to 6 months. If left in the ground tubers can grow massive.
NOTE: I did not find any notations of sweet potato weevils or root knot nematode damage however the ñame I purchased appeared to have minor root knot nematode damage.