Best plant-based fibers for making pot holders

Does anyone have suggestions for material for making woven pot holders?
Usually I just use loops from worn-out cotton socks, but I'm out of worn-out socks for the moment. And lately none of the socks I can find are pure cotton anyway, they usually have some synthetic fibers that melt in heat.

I'm looking for a material that is flexible enough to bend, so it can be used to grab pot handles, reasonably non-heat-conductive, and not very flammable.

I've been thinking of trying Phormium fibers, but I'm worried it'll be either too thin to insulate or too stiff to bend properly.

Anyone have suggestions / experience?

Is there a reason you're favoring plant-based?

I use oven mitts rather than pot holders myself, and used to find they weren't quite insulating enough, so I cut section out of my worn out wool socks and sewed in on the inside of the oven mitt in the area that needed the most heat protection.

Do you have or can you find 100% cotton T-shirts to use instead of the socks?

A friend of mine used to knit potholders that just went over the handle of the pan, and they worked pretty well if they were knit tightly enough.

If you look at commercially made potholders, they are usually knit with thicker yarn, or made with a woven material which has some other form of batting in between quilted layers to retain the shape.