This is an old
thread but it's got conflicting anecdotes about whether apios like wet feet or not. After five years of having them -- I won't say growing -- I am here to reconfirm that they aren't very fussy in the sense of being very hard to kill, but the ones I have, which were found in wet soil, much prefer saturated soil in my garden to any other option.
As I mentioned five summers ago, my sister found some wild apios in saturated soil along her lake shore here in central Oklahoma. I took them home and I still have them. Frankly, as an unimproved variety I don't really eat them; the tubers are small and they haven't impressed me a lot with their taste or texture. But I maintain them, because it would take work to stop.
I've had them in every type of pot and container in my container garden. (I tend to only grow tall stuff in the ground because it's not good ground, it's full of eaters, and it's
way down there, where my not-very-bendy self has a hard time engaging with stuff properly.) Every fall after the foliage dies off, they sit around somewhere until spring. And every spring, I look at that pot (which looks dead/empty) and go to dump it in my soil bin, whereupon I find the string of apios tubers. So I plant them in a new pot, they grow all summer (usually making a nuisance of themselves by climbing/strangling something I like better) and the cycle repeats. But they also SPREAD, because any little string or micro-tuber that I miss when I'm repotting winds up in some other pot, and the distinctive apios foliage pops up in mid July after struggling to the surface from wherever it was buried some random nine inches deep or whatever. So I have lots of these. It would not be unfair to say they are like weeds, albeit welcome ones, in my container garden.
What I have learned over time is that in my dry/hot summer conditions, the best way to keep them is to put whatever pot they are in in some sort of
bucket or tub that's about half as tall as their pot, and then just keep that lower tub completely full of
water. That way, they are always in very wet if not saturated soil. They grow better that way. Drying them out does not kill them, but the foliage dies back massively and they may be done for the year, or at least until they get a couple of weeks of wet.
This year, for the first time, I got profuse flowers. I don't believe it's a coincidence that I kept their feet wetter than ever before, in a bigger tub. I have always been a little bit uncertain that I had apios, to be honest; it's one of the reasons I haven't talked about them much. But the flowers are distinctive: