I have had these lilies in my pond forever. They always covered the surface til this year. I have 3 on the one side and 1 on the other. The lilies did not come up like they have in the past on the one side. Just a few pads. When I noticed one container didn't come up at all, I pulled it up and dug through the gravel and noticed the tuber was just mush. Is it normal for a tuber to die like that?