Lots of great stuff here. I learned that the flowers that I know as white jazmine ginger are white garland-lily! (I looked it up in Wiki when I saw your ID. ) It is one of my favorites for its butterfly-like flowers and its jazmine -like perfume. Our house right now smells wonderful especially so at night--the flowers are blooming and are featured in our cut flower arrangement. The plants disappear sometime after the fall blossoming and then reappear from the rhizomes months later-- similar to the one you call turmeric (see my note). And it is another noxious weed, according to Wiki!!! It is a strange world we live in when some of the most beautiful things are "invasive."