Water hyacinth (Eichhornia crassipes)
Invasive water plants have a direct impact on Texas lakes.
One such non-native species is the floating water hyacinth, which often has showy lavender flowers. Invasives thrive when introduced into areas where they have no predators or disease control. They quickly reproduce and grow unchecked, crowding out native species that use the same habitat.
Other invasive water plants in Texas include hydrilla, alligatorweed and water lettuce.
Water hyacinth is a large aquatic plant native to the Amazon basin. This invasive nuisance floats on water and can spread from fragmentation and seed production. The peak flowering time for this invasive species is late summer and early fall, according to the Texas Invasive Species Institute.
The plant can produce thousands of seeds a year that can be viable for up to 30 years, according to the U.S. Fish and Wildlife Service. The plant is one of the fastest-growing invasives, with the ability to double its population in just two weeks.
What makes water hyacinth a pest is its ability to grow into thick layers over water.
These thick layers can shade out other aquatic plants and can negatively impact the dissolved oxygen levels, affecting other plant life and the fish population. The USFWS said that these thick layers of hyacinth could also interfere with boat navigation and recreational activities.
In the Brazos River basin, hyacinth was an issue for Lake Limestone in 2002 and 2003. Starting off as a pest for the upper portion of the reservoir, it migrated into the Navasota River below the dam. It was cleared naturally, and no reports of sightings have been received since that time.
Water hyacinth is often used in water gardens and was introduced in the United States in the late 1800s.
The BRA works to prevent the spread of invasive species by supporting Texas Parks and Wildlife’s public outreach campaign. The BRA also performs routine observations by environmental services staff that identify exact species, assess threats to reservoirs, and treat if needed.
The biggest threat to our ecosystem when invasive species are introduced would be the reduction of natural biodiversity, reduced food source for native wildlife, and low dissolved oxygen problems.
Prevention is key to stop the spread of invasive plants such as hyacinth, hydrilla, alligator weed and water lettuce. If you visit waterbodies known to have invasive plants, please follow TPWD’s recommendations to clean, drain and dry your boat, canoe, or kayak before visiting other water bodies.
As a non-native plant, it is illegal to possess or transport water hyacinth in Texas. Report sightings to the Texas Parks and Wildlife Department at (512) 389-4800. If you observe Alligatorweed on any BRA reservoir, please also photograph and document the location and report the sighting to the lake office.