It don’t think it’s enciphered, Laura. I think it says “rot” (it’s written the same way horizontally in another plant, pointed out by MarcoP). It’s probably German for “red”.

Thank you, Nick. And thank you for calling my attention to Dark Archives (great name) and Charles Burnett. I was unaware of either one.

One of the talks in the recent Dark Archives conference extensively discussed the same cipher in the context of early mediaeval ciphers. Charles Burnett also wrote at least one paper on it, calling it the “magical alphabet” because of its frequent appearance in charms and other magical recipes.