Pistia, also known as “water lettuce,” is an unusual tropical floating plant: its roots absorb nutrients directly from the water, significantly reducing algae populations.
Water lettuce has charming, thick, velvety leaves that resemble a seashell. Their color can range from light green to dark green. From the center of the rosette, light green roots float downward without anchoring to the bottom. On larger plants, the rosette can reach up to 20 cm in diameter. From the center of the rosette, small (less than 1 cm) pale yellow flowers with a greenish-white appear, somewhat resembling a calla lily bloom.
In just two weeks, pistia can triple its biomass in a nutrient-rich reservoir. In tropical regions, water lettuce is considered a nuisance weed, rapidly overgrowing water bodies. In Estonia, this is not a concern. If the water temperature drops below +15 ºC, the plant dies. It should not be allowed to sink after frost, as all absorbed nutrients will return to the water. At the beginning of September, the plants should be collected and composted – by next spring, they will make excellent material for other plants. A few specimens can be brought indoors. They can overwinter quite successfully in a wide, medium-height glass container on a sunny windowsill. The dangling roots are a visual bonus and can be beautifully displayed in a transparent vase, though any watertight container will do.
