Self-heal, Prunella vulgaris. Otherwise known as Heal-all, guess what it’s used for.
Well some people just eat it. The leaves are edible but not especially tasty. It’s main use is as a medicine and as the name suggests it can cure you of pretty much any ailment. (If a Crocodile bites your head off and you rub this on the stump then you will grow a new head)
For this reason, if you are in the habit of drying leaves to use as herbs anyway, why not add a few of these? Just in case.
Otherwise just look at it, it is beautiful.