Never used ginger but I use Hibiscus in a Saison and a Gose, the flowers go in at flame out and steep like a hop stand. The results are great, nice floral notes and color contribution. The floral aroma will fade a bit. I used the bag from Jamaica as well, about 2/3rds IIRC.
Did you use the whole bag, Gary? I'd thought of doing that, too, but wasn't sure how much flavor it would bring.
No, I used 45 grams which if I remember was a bit less than the entire bag. They steeped for about 30 minutes before I began chilling. This is reminding me to order some more so I can get my Gose on for the warmer weather which I hope is coming soon!