Species Overview

Native to: India, Malaysia

East Indian hygrophila was introduced into Florida waters as an aquarium plant prior to the 1950s. However, it escaped cultivation and began invading slow moving waters in south Florida. 

Species Characteristics

• Family: Acanthaceae
• Habit: perennial aquatic herb with squarish stems ascending to creeping; mostly submersed, usually rooted in substrate; also roots freely at floating nodes
• Leaves: opposite, usually broader toward tip; sessile, with bases joined at node by ciliated flanges of tissue, the cilia (hairs) easily observed
• Flowers: small, solitary in uppermost leaf axils, nearly hidden by leaves, calyx 5-lobed, corolla bluish white, 2-lipped; 2 fertile stamens; blooms during fall and winter in Florida
• Fruit: narrow capsule, splitting lengthwise to release 20-30 seeds
• Seeds: flat, round and minute
• Distribution in Florida: throughout, with limited distribution

Impacts

Hygrophila is a fast-growing aquatic invasive that can outshade and outcompete other submersed plants. It can grow to occupy the entire water column and forms dense mats, blocking light penetration below. Hygrophila produces adventitious roots at stem nodes, therefore fragments can easily grow into new plants.

Hygrophila clogs irrigation and flood-control canals by forming large mats which collect at culverts and interfere with essential water control pumping stations. It also interferes with navigation and can grow from the water's edge to depths up to 10 feet.

Hygrophila is prohibited and therefore not recommended by UF/IFAS. Hydrophila is on the USDA Federal Noxious Weed List and the FDACS- Florida Prohibited Aquatic Plant List. The UF/IFAS Assessment lists hygrophila as prohibited, with high invasion risk. It is listed by FLEPPC as a Category l invasive species due to its ability to invade and displace native plant communities.

Transporting plant fragments on boats, trailers and in livewells is the main introduction route to new lakes and rivers. Cleaning all equipment after use is one way to prevent spread of this prohibited plant.

Do not purchase or collect hygrophila for use in aquariums or ornamental ponds. 

Because hygrophila spreads vegetatively, by fragments, mechanical harvesting and chopping machines may increase its distribution.

There are no known biological control agents for hygrophila.

Several registered aquatic herbicides may provide temporary control of hygrophila. See: Efficacy of Herbicide Active Ingredients Against Aquatic Weeds to learn more.