Delta arrowhead
Sagittaria platyphylla
Washington State Classification
Class A — Eradication Required Statewide
Delta arrowhead is a highly invasive aquatic weed in Africa, Australia, Asia, and Western North America.
Quick Reference
Identification
Growth Habit
Delta arrowhead is a perennial, herbaceous, aquatic plant, which can emerge by up to a foot from water surface.
Leaves
Leaves can be submerged below the water and can emerge arching above the water. The underwater leaves can be lance to arrow shaped, while the above-water leaves are never arrow-shaped.
Flowers
Clusters of 3 petaled white flowers grow on bright green stems above the water in the summer. At the center of the petals are yellow stamens or bright green fruits beginning to form. Each cluster of flowers has 3 to 9 flowers.
Fruit & Seeds
The bright green seed heads break into several thin brown seeds as they mature.
Impact
Delta arrowhead is a highly invasive aquatic weed in Africa, Australia, Asia, and Western North America. In waterbodies, it outcompetes desired vegetation, hinders recreation, and reduces wildlife habitat. It floats easily to new sites and can heavily impact drainage and water infrastructure.
Ecology & Spread
Habitat
Delta arrowhead grows along the shallow margins of lakes, ponds, streams, rivers, and man made drainage and irrigation channels and ditches.
Spread Mechanisms
Reproduction
Asexually via stolons. Chunks of plant can float to new sites. Also grow from seed.
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