Sagittaria sagittifolia

Notifiable Organism, Unwanted Organism, National Pest Plant Accord

• Arrowhead 

• Scientific Name: Sagittaria sagittifolia
• Origin: Native to Asia and Europe
• Type: Weed
• Plant Life-form Type: Marginal erect/tall
• Taxonomy: L.
• Presence: Locally naturalised, first record from Coromandel Peninsula in 2002.
• Habitat: Still and slow flowing water bodies and wetlands.
• Temperature (°C): Dec-24
• pH range: 7.2 - 8.0
• Hardness (ppm): 100 - 150
• Notes: A potentially important irrigation weed; poor dispersal capacity has limited current spread. This species has been included in this survey only to demonstrate a use most Sagittarias have in SE Asia. The rootstock or corm of many Sagittaria species & particularly S. sagittifolia is farmed as an edible vegetable somewhat like taro. I have also used its emerged leaf form to illustrate the extremes in shape.
• Propagation: Apparently by deliberate planting and subsequent spread by water movement. Possibly cultivated as a vegetable by some ethnic groups
• Features: Tall summer-green perennial dying back to underground parts over winter. Emergent leaves have a distinctive glossy arrow-shape with long basal lobes. Petioles are triangular in cross-section. Rhizomatous with round tubers, up to 3 cm across, produced on these. No flowers seen on New Zealand material.
• Source: TIFBIS
• Regional: Regional Pest Management Strategy: AUK, WKO, WGN.