My sister has been distilling mugwort and selling the hydrosol. I was curious how people were using it and assumed, since it is to be distilled during a full moon, that it is probably a magical use.
I remembered that we had long ago acquired a booklet by Adelma Simmons titled, "Midsummer Magic and Mugwort" and went on an all-out hunt for the booklet. I thought it would be fun to see what she had to say about it before I consulted the internet.
If you don't recognize the name Adelma Simmons, she was one of the first "famous" herbalists in the modern era. Her farm was named Caprilands and she was well known in the herbal community.
After a relatively short time, I located the booklet:
After doing a quick search on the trusty internet, I found that probably the reason people want the mugwort hydrosol is for the same reason they want her white sage hydrosol, for protection and cleansing of negativity.
I could have just checked her website - as I did to find the links - and would have found the same answers.
Both are used in a similar manner to smudge. Smudging usually involves smoldering herbs so that the smoke will cleanse a space, but these lovely, fresh sprays will do the same job without having to burn anything or smoke up the house.