I used a bit of each herb in the boil, and then also in the Primary after the 1st week of fermentation was done... sort of like dry-hoping.. with the sweet gale & yarrow, I definitely wanted to preserve the aromatics.
I brewed one small batch using Yarrow, sweet gale, mugwort, and a little Damania. Turned out sweet, slightly tart and tasted pretty much like carbonated grapefruit juice. I liked it but wanted a more complex flavor profile.