It's so true about not needing as much spice or flavoring when using sheep sorrel! Fun to snack on by itself too (in small quantities)!The "sheep" is likely to suggest a difference.
However, the flavor description is a good match with my sorrel experience.
It was on the perimeter of one garden that I had - the one on the bank above the river. How it came to be there, I don't know. The docks are common here but not that one, I don't think.
A spicy taco wouldn't need to be quite so spicy with the lemony, the mustard and the black pepper flavors.
Steve