Alternative common names:
Broad-leaf arrowhead, delta duck-potato.
The delta arrowhead is an aquatic plant growing up to 150cm tall. It is green in colour, fast growing and can be placed in a variety of locations within an aquarium. The plant reproduces by means of stolons as well as seeds. Some leaves are totally submerged, others emergent (rising above the surface of the water). Submerged leaves have flattened petioles, but no true blades. Emergent leaves have ovate to elliptical blades.
Where does this species come from?North America.
What is its invasive status in South Africa?NEMBA Category 1a
Where in South Africa is it a problem?KwZzulu-Natal, Eastern Cape and Western Cape.
How does it spread?Dispersed during floods and in dumped aquarium and garden waste. They also facilitate the lateral spread of colonies over time. The seeds are thought to be spread by water movement and animals.
Why is it a problem?
The plant threatens indigenous aquatic flora and fauna. Dense infestations restrict water flow and can substantially alter the flow regime of catchments and waterways, affecting biodiversity and stream health.
What does it look like?
Leaves: The emergent leaves are large (10-48cm long and 2-10cm wide) and borne on long stalks up to 55cm long. These stalks, which are up to 25mm thick, are triangular in cross-section and are slightly winged towards the base. The leaf blades are elongated or narrowly egg-shaped in outline, with entire margins and pointed tips. They are hairless and have a shiny appearance. The underwater leaves are strap-like in nature (up to 50cm long and 10-25mm wide) and form a rosette below the water surface.
Flowers: The flowers are about 30mm across, white or sometimes pinkish in colour, and are arranged in 2-12 groups of three near the top of the emergent flowering stems. Flowering occurs mostly during summer and autumn.
Fruit/seeds: The fruit consists of a mass of numerous one-seeded fruitlets that are densely arranged in a small rounded cluster (5-15mm across).
Does the plant have any uses?
It has been cultivated as an ornamental.