well my pond sprung a leak so i took all the fish and plants out for a couple of days. i threw the water hyacinth on the grass but forgot to get it again. it was two days till i realized they were out! the smaller ones were shriveling up already. they all were dry. so anyway i put them in my tanks as soon as possible. less then five hours later a flower started to open up. the next moring it was opened up even more so i left the room and when i came back it was almost opened long story short in fifteen minutes it was completely open! wow. it is a pretty hardy plant!
i hope those plants grow.