Rooted water hyacinth
Native to: Central and South America
Rooted water hyacinth was introduced to the U.S. via the ornamental aquatic plant garden trade. It thrives in slow moving waters from rivers, marsh lands, and lakes. While a few populations have been documented and eradicated in Florida and Texas and a few may still remain, it is not known to be a widespread problem in North America. However, due to its potential invasiveness it is listed as a Federal Noxious Weed.
Family: Pontederiaceae
Habit: Rooted perennial aquatic.
Leaves: Alternate, submersed leaves sessile, emersed leaves stalked. Thick green waxy elliptical leaves are formed in rosettes and gently incurved.
Flowers: Showy purple flowers above water surface on erect stems, 7-50 flowers per stalk.
Fruit/seeds: Three-celled capsules with many seeds.
Distribution in Florida: Vouchered in Columbia county.
Note: Can be confused with the widespread invasive Water hyacinth (Eichhornia crassipes) but is distinguished by its elongate, fan-like submersed leaves and long floating stems with large obovate, erect leaves with slender petioles and secondary submerged roots (coming from stem nodes). The petiole of the emergent leaf is never swollen. Flowers are similar but are often less robust and more blue in color. The inner petals have a fringed margin. E. crassipes can float freely, unlike E. azurea, which must root to the substrate and is therefore confined to shallow ponds and the edges of lakes and rivers (Barrett, 1989; Q-Bank, 2016).
Can be easily spread vegetatively, with plant fragments hitchhiking on boating and other equipment. It can form dense, impenetrable mats which clog waterways, making boating, fishing and almost all other water activities, impossible. It can also reduce biodiversity by crowding out native plants at the water's surface and below and degrade water quality by blocking the air-water interface and greatly reducing oxygen levels in the water, eliminating underwater animals such as fish.
Do not plant. Always clean boating equipment when moving between water bodies.
Hand-pulling can be effective on small populations.
Harvesters may be used.
Neochetina eichhorniae, N. bruchi (weevils), and Niphograpta albiguttalis (moth larvae) have been used in tropical and subtropical populations.
Likely can be treated similar to E. crassipes (water hyacinth) as follows: Foliar (diquat dibromide, 1-2 quarts/acre smaller plants, up to 3 qt/ac for mature plants). Frequent applications may be required. Consult your local UF IFAS Extension Office for management recommendations.
