Howdy!
I hope you were able to find an
answer before this, but if not ...
I have been a fan of
https://www.fabrics-store.com/ for years and years. All the linen I get from them is amazing. I have several stacks of it, even now, and just got done taking an experimental pattern for a men's shirt apart as it had truly wacky proportions.
Their linen has an amazing hand,
I tend to torture it when it first arrives -
hot water, lots of agitation, throw it in a super hot
dryer - it always retains it's color and is just so soft!! (I have made a few chemises out of it just because it's amazing.)
They also have had some other plant based fibers, mostly cotton or rayon and some blends with those two.
The only major seller of the more interesting plant fiber products, to my knowledge, is Dharma Trading.(
https://www.dharmatrading.com/)
I'm sure there are others, but I haven't been looking that hard for alternative fibers recently.
Dharma carries cotton, flax, and bamboo and they used to have some hemp products, as well as
nettle yarn. I bought my "fiddle with"
nettle yarn from them many moons ago, so they might have stopped selling it. They are a good company and have always sent me exactly what I ordered, even if it means that I have at least a summer's worth of natural indigo and assorted dying supplies.
I hope this helps.
I understand the frustration with trying to find a good company that sells whatever you are looking for. I hope you have great luck with those two companies!