Why does the Corps’ program target water hyacinth and water lettuce?
Water hyacinth and water lettuce are invasive, nonnative plants whose growth rates are among the highest known of any plants. Because their populations can double in 7 to 12 days, 10 of these plants can grow to cover 1 acre in a single growing season. The high productivity of one acre of water hyacinth or water lettuce can deposit about 1.7 tons of organic material (dry weight of leaves, stems and roots) on the bottom of the water body per year. A one-acre floating mat commonly weighing 250-300 tons (fresh weight) can damage water control structures, bridges, and docks. Hyacinths and water lettuce also obstruct navigation, out-compete native plants, and upset the natural balance of the aquatic ecosystem. Dissolved oxygen, necessary for survival of fish and invertebrates, is lacking beneath the center of large mats.
