Water hyacinth is an aquatic plant that grows aggressively in free-floating mats. Its dangling roots provide nutrients from the water, but it reproduces by seed and vegetative daughter plants. The leaves are round to oval, growing small or up to ten inches. The leaf stalk is thick and spongy, helping with flotation and holding the leaves upright. The attractive blue-purple flowers have a yellow spot and are held above the plant on a flower stalk.
Though it’s a native of South America, water hyacinth is more or less naturalized in the south-eastern United States. It thrives in more temperate climates, but can survive mild freezing conditions in states where it is established. It also reproduces prolifically: in one study, two plants produced 1,200 daughter plants in four months. In ideal habitat, population can double in as little as seven days. A plant can produce 5,000 seeds, which can float or be carried by birds to new locations. Thick mats degrade water quality, restricting water flow and reducing oxygen levels.
If you find this weed on your property or around Teton County, please report it immediately at 733-8419.