Wednesday, December 29, 2010
The pond in the herb garden at the UC Botanical Garden is now covered with a beautiful layer of duckweed. It almost looks like a lawn. And, according to some stories I have heard, it looks so much like a lawn to some kids that they try to walk on it. AND FALL IN! So, kids, stay out of the water. That green stuff that looks like a putting green is actually thousands of tiny plants floating on the surface of the pond: duckweed.
It is called duckweed because ducks, and other waterfowl, eat it. It is very high in protein. Higher than soybeans. So it is a great food source for birds, and some humans use it, too. It has been used for many generations in Thailand, Burma and Laos. Some people call it watermeal; I guess because you can eat it like cornmeal, and the individual plants are about the same size as a grain of cornmeal. Pretty small! Wolffia angusta and Wolffia globosa, two species in this family, are the smallest plants in the world and have the smallest flowers in the world.
Watermeal grows so quickly it can be harvested every few days, so it can be a good food source. But this also means that it can clog slow-moving waterways. Many online sites address this plant as a pest and offer control methods. Why not just harvest it and eat it? In fact, it is used to clean up pollutants in water treatment plants and then fed to fish and chickens. That seems good, but perhaps some creative people will come up with some more ideas about how to use this plant.