hydrilla

Hydrilla, scientifically known as Hydrilla verticillata, is a submerged perennial aquatic plant that has become one of the world’s most troublesome invasive species in freshwater systems. Native to Asia and Africa, it has been introduced widely in North America, Europe, Australia, and other regions. It spreads rapidly and forms dense underwater and surface vegetation that can outcompete native plants and alter aquatic ecosystems.

Morphology and growth: Hydrilla has slender, branching stems with leaves arranged in whorls of four to eight along the stem. Leaves are narrow, with serrated margins and lengths typically ranging from 1.5 to 5 centimeters. The plant is well adapted to low-oxygen substrates and can produce tubers underground and seasonal turions that help overwinter and spread. It can grow in a wide range of water depths and nutrient conditions, often reaching the water surface to form mats that shade out other aquatic vegetation.

Ecology and impacts: Hydrilla reproduces primarily through vegetative means—fragments, tubers, and turions—making containment challenging. Seeds, if produced, are uncommon. It forms dense stands that reduce light penetration, deplete oxygen, hinder navigation and recreation, and interfere with irrigation and hydroelectric infrastructure. Its persistence and rapid spread lead to substantial ecological and economic impacts.

Control and management: Effective management typically requires an integrated approach. Methods include mechanical removal, barriers, and the targeted use of aquatic herbicides such as systemic and contact formulations where permitted. Early detection and rapid response are crucial to prevent fragmentation and further spread. Public awareness and preventive practices, including boat and equipment cleaning, help limit introductions to new water bodies.