Many years ago, when I was experimenting with container water gardens, I came across some mysterious seedlings growing in the bottom of a half-whiskey barrel.
This was in early March. I had brought the barrel inside my greenhouse for the winter to overwinter a small tropical water lily. The main experiment had not been a success. The water lily had weakened under the short days and cool temperatures of the greenhouse, so I finally had to move the plant to a warmer spot under intense artificial light and that meant into a much smaller container. The barrel was just too big.
Still, I simply left the container there, nearly full of clear water, without giving it any special attention. And that’s when I noticed something growing at the bottom. Yes, under water! A few seedlings had appeared and were growing there, seedlings with simple, lanceolate cotyledons, rather thick… I would have said they were something like little amaryllis (Hippeastrum) leaves. I had no idea what they could be, but they were growing quite vigorously, and I was more than willing to give them a chance. Besides I had never seen seedlings sprout underwater before, so I was intrigued.
It’s unfortunate that I didn’t think to take any photos, but—what can I say? I didn’t! The next leaves that came in were rounder, but still unrecognizable to me. Shiny, green, with a short, thick petiole. What could they be?
Relics of the Previous Summer
I got the answer one morning in April, when the little seedlings suddenly turned up happily floating at the surface of the water. Why, they were baby water hyacinths (Pontederia crassipes, formerly Eichhornia crassipes), of course! It would appear that water hyacinth seeds germinate underwater, root in the soil there, then rise to the top to take up their usual floating lifestyle when they’re good and ready.
I had been growing water hyacinths in the half barrel the summer before. Clearly, they had produced seed without my noticing.