Arrowhead

Sagittaria sagittifolia

AKA: Old World Arrowhead, Water archer, Swamp potato

Arrowhead is a tall aquatic plant often found in shallow water or in the margins of slow-moving watercourses. It has three different leaf types: large emergent arrow-shaped leaves measuring 5-20 cm long on long stalks; submerged leaves which are linear and translucent and can measure up to 80 cm long and 2 cm wide; and floating leaves which are oval-lanceolate in shape.

Arrowhead flowers appear in July to August. They are small only measuring 2-3cm in diameter and have three white petals, with a purple-black spot at the base. The flowers occur in whorls of 3-5 around a spike (raceme) measuring 30-80 cm tall. The lower flowers are female with many carpels, whilst the upper flowers are male and tend to be larger and longer-stalked with many purple stamens.

The plant overwinters by detached submerged buds.

Where and when to see them

The flowering plant is found in still or slow-moving fresh water from June to September, but if you want to see the flowers they are only present during July and August.

View an arrowhead 10km distribution map of Wales

Legal status

None.

Similar species

None, the leaves are very distinctive.

Did you know?

According to Wikipedia, arrowhead (S. sagittifolia) is cultivated as a food crop in some countries, and is used in Chinese medicine as it has anti-microbial properties.