Hardy Yam - Dioscorea

Yes, now I checked my Chinese Yam. Indeed it has a root in the base of the pot. It was not very large, not going all around. There was a small piece of root going through a hole at the underside. That part broke off. I think that is no problem. I put everything back in the pot with some new 'potting soil' mixed in the old soil. Hoping it will grow again next year.

I've been neglecting my yam plants this year; I had plants started from Japanese and Chinese yam bulbils, but both are still in tiny pots from last year. They've dried out on the window sill and are outside getting soaked in the summer rain now - tough little things! Hopefully I will be able to transplant them into my new polytunnel soon and give them a proper place to live.

Update on my Yam in a large pot: this year it looks better than ever before!
I don't think I'll harvest anything from it. It's a nice decorative vine-in-a-pot.
Photo made today, August 17, 2025:

My yam (Chinese) is four years old and has not spread. They seem to be very resilient and blend right in with the bindweed, which they resemble. They are climbing up a small willow tree. I have eaten a few aerial tubers raw and they are good—they very much resemble Bolboschoenus fluviatilis in flavor.

I suspect mine are Dioscorea polystachia, obtained from a friend, who possibly got his from RealSeeds in Pembrokeshire, UK. A lot of their leaves are opposite, and the bulbils are tiny.
My tubers are planted individually in rose pots - tall plant pots. They're kept indoors in that state, I start watering in spring to encourage growth - but they'd probably start anyway. I'm aware slugs like them, so I'll only put them out when there's a good length on (raspberry canes are useful for climbing)).
Summer quarters are on an old dustbin of good compost. It's got a small hole 6 to 8 inches up - in a wet summer I've had the water table up to the surface without that. The yams send their roots down into the compost, no further than the water table (that'll be right at the bottom this dry year). Tops grow into a hazel, I introduce them to hanging twigs (less chance of snail attack).
In autumn I lift the pots and protect from frost. Then tip the bin and harvest the roots, dry them off and store in a plastic bag with my spuds. But first I check the pots - some will have given their all to the root in the bin, and there's no root in the pot. So I ensure there is a length of root in the pot for next year.
Hardiness: there was one year I was late harvesting, and freezing weather had arrived. Mush in the pots. Mush in the bin - until right at the bottom, some unfrosted root. In the ground the frost wouldn't have penetrated so deep, and I may have had a root breaking from deep. But, as others have said, extracting this root is no joke! Deep, brittle and thicker at the bottom. Someone cross it with carrot...

M Ljin wrote:My yam (Chinese) is four years old and has not spread. They seem to be very resilient and blend right in with the bindweed, which they resemble. They are climbing up a small willow tree. I have eaten a few aerial tubers raw and they are good—they very much resemble Bolboschoenus fluviatilis in flavor.

Is Bulboschoenus aka Scirpus fluviatilis? as detailed here - https://pfaf.org/user/Plant.aspx?LatinName=Scirpus+fluviatilis

Anthony Powell wrote:

M Ljin wrote:My yam (Chinese) is four years old and has not spread. They seem to be very resilient and blend right in with the bindweed, which they resemble. They are climbing up a small willow tree. I have eaten a few aerial tubers raw and they are good—they very much resemble Bolboschoenus fluviatilis in flavor.

Is Bulboschoenus aka Scirpus fluviatilis? as detailed here - https://pfaf.org/user/Plant.aspx?LatinName=Scirpus+fluviatilis

Yes. I would like to start a whole new thread on them—they are amazing!

I have a plant that I have been growing for several years. I started it from aerial tubers I bought online. It grows really well, but it has only ever produced a handful of pea sized aerial tubers over the entire time I’ve been growing it. I’m curious why that is. I don’t water it very much, and I’m a mile from the ocean on the California central coast. Maybe water is the issue? It never appears water stressed no matter how dry it gets.

Anyone else have plants that refuse to make aerial tubers?

jaime merritt wrote:I have a plant that I have been growing for several years. I started it from aerial tubers I bought online. It grows really well, but it has only ever produced a handful of pea sized aerial tubers over the entire time I’ve been growing it. I’m curious why that is. I don’t water it very much, and I’m a mile from the ocean on the California central coast. Maybe water is the issue? It never appears water stressed no matter how dry it gets.

Anyone else have plants that refuse to make aerial tubers?

I reckon water could be the issue. We've had a dry season in England, roots that usually grow through the bottoms of their pots haven't. And the top growth wasn't so strong either. I'll be ensuring they get enough next year!
I've only ever had a scattering of aerial tubers off my 5 plants, no more than sweet pea size - hardly worth propagating from, let alone eating. Could be the species/variety. Easiest to propagate by breaking the root.

jaime merritt wrote:I have a plant that I have been growing for several years. I started it from aerial tubers I bought online. It grows really well, but it has only ever produced a handful of pea sized aerial tubers over the entire time I’ve been growing it. I’m curious why that is. I don’t water it very much, and I’m a mile from the ocean on the California central coast. Maybe water is the issue? It never appears water stressed no matter how dry it gets.

Anyone else have plants that refuse to make aerial tubers?

Maybe my Yam is not the kind that makes aerial tubers. It only makes a vine with leaves.

I grow D. Alata, one white and two purple varieties. One of the purple varieties are extremely vigorous and grow and interesting square vine. I also grow pentophilia, it is my first year growing it and I don't have a lot of experience with it yet. What I can say about all of these yams, is they like to grow up. They have a very distinct ability to tell which direction they are growing, they grow sideways rather quickly, but nothing like when they grow straight up. If they grow sideways and can't find anything to grab onto, they will slow and growth, eventually twisting around on themselves in growing the other way, this wastes energy. They do not do good sprawling on the ground, and despite what many have said, they just do not do well in containers, I believe they need to tap into a larger mycorrhizal Network. I am amazed at how fast they can grow when they are allowed to climb straight up.

Jason Buzzard wrote:... despite what many have said, they just do not do well in containers, I believe they need to tap into a larger mycorrhizal Network. ...

Thank you for this information. In that case I'll get it out of its container and plant it somewhere in the garden where it can still do its climbing, but not in the hedge (in which it climbs now).