They survived till about September, here, September is still very warm. I put them in clay pots about 8" diameter in native (silty, stoney rather poor) soil submerged in, like I said, a 20 gallon tub. Our city does douse the water with chloramine. Per my somewhat faulty recollection, at the start I treated the water with chloramine remover (some sort of hydrosulfite stuff I use for my koi pond) I did add a very small amount of miracle grow. Yeah, they're supposed to be fairly easy, I've seen them growing like mad in Japan in very warm weather. Probably need much bigger pots with richer soil and always use chloramine remover when topping up the container???? Or use koi pond effluent? Some day I do want to start a proper water garden, separate from the koi pond, I find they'll eat just about anything except cat tails and horse tails....