My sister planted rue in the original herb garden in 1992. It was several years, before I figured out that it was what caused a deep darkening of the skin on my hands when I came in contact with it. It, like parsnip foliage, causes your skin to react if you get it on it and the sun shines on the skin.
So I was careful working around it after that. It died about 10 years ago and I never replaced it.
Oh, I never realized that. you are saying it is photo sensitive.
I am well aware of the St. John´s wort oil I make here has the same issue.
you can not apply it to your skin and then have it exposed to sun light.
thanks for sharing this, very good to know 🙏