Wierd Plant Fibers: How to harvest?!?!

Hey guys,
I just bought some rose fiber to spin. Its soft and lustrous; nicer than silk, in my opinion. The same storefront sells Mint fiber from peppermint! They say it is cooling and breathable, which in zone 7, I value... but how did the fiber get out of the rose or the mint? Do we think the same way as processing nettle? All I know is, this is very cool and I want to be able to do it myself! Ideas, pointers, certain knowledge, all welcome.

It is usually rayon processing.   But we would have to know more about the source to be sure.  Maybe try the burn test.

https://byhandlondon.com/blogs/by-hand-london/the-burn-test-how-to-identify-the-fibres-in-your-mystery-fabric

I really enjoyed the thread about spinning nettles.

I have also read some on the forum about milkweed pods.

I just happened on this youtube that might be interesting: