No Rest for the Wicked *SPOILER ALERT*

Does anyone know what plants you’re supposed to get for the potion that will dye the water red?

I think they are:

Nettles
St. John’s Wort
Poppies

But I’m not sure. Please let me know if you’ve figured this out. Thanks.

thistle not nettle
It makes sense cause thistle also has a red flower

Thank you.