Sagittaria

Also known as:
Delta Arrowhead
Family:
Alismataceae
Origin:
North America

General description

Emergent, perennial <80cm high. Fleshy rhizomes usually submerged below surface. Leaves either emergent (ovate, tapering to point on triangular winged stem) or submerged (strap shaped), held above surface by rigid stems. White - pink flowers (Nov-Mar) in clusters of 3-flowered whorls; flowers always below leaf height.

Static or slow moving freshwater <45cm: drains, streams, pond margins.

Locally spread by creeping roots. Seeds carried by water, wildlife, machinery. Rhizome fragments spread by machinery.

Extensive infestations block waterways impeding drainage, disrupting recreational activities. Out-competes native species

Site management

Regular follow up required.

Recommended approaches

1. Report it immediately to the Auckland Council Biosecurity team, which will arrange for its control at their expense.
2. Dig out plants removing all plant material.
3. Spray emergent plants before they flower and seed (200ml glyphosate/10L, use glyphosate formulation approved for use over water).
4. Palatable to grass carp, refer to DOC.

Caution: when using any herbicide or pesticide PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed.

Similar species

eel grass - Lake Pupuke variety
Vallisneria australis

Eelgrass leaves look similar to Sagittaria's submerged leaves. Eelgrass does not emerge above the water.

eel grass - Meola Creek variety
Vallisneria spiralis

Eelgrass leaves look similar to Sagittaria's submerged leaves. Eelgrass does not emerge above the water.

RPMS status

Total Control - Whole Region
National Pest Plant Accord species - nationwide
sagittaria - Main species image