Alisma canaliculatum

Alisma canaliculatum is a wetland perennial in the Alismataceae family. Its native range spans parts of temperate Asia. Kew records it from the Himalaya to Assam. Its range also covers central and eastern China, temperate East Asia, and the Kuril Islands. Plants For A Future lists Japan, South Korea, and Taiwan. It grows in wet sites across Japan. In China, it grows beside lakes, ponds, marshes, and streams. These habitats give a clear guide to its garden needs.

This plant reaches about 2.6 feet [0.8 metres] in height. Its perennial habit makes it a lasting planting for wet ground. Kew classes it as a helophyte, a plant of marshy ground. The supplied species accounts give no details of leaf shape or stems. They also give no mature spread. Flowers appear from June to August. Each flower has both male and female organs. Flies pollinate the flowers, and seeds ripen from July to September. The evidence gives no species-level account of flower colour or fruit form.

Grow it in full sun, with wet soil throughout. It does not grow in shade. Boggy ground and shallow water both suit it. Plants For A Future gives a water depth of 0.8 feet [0.25 metres]. It accepts sandy soil, loam, and clay. It also tolerates mildly acid, neutral, and mildly alkaline conditions. Pond margins and bog gardens match these needs. The source lists USDA zones 5–9. It also reports a UK zone of 6, without an RHS hardiness code.

Raise plants from fresh seed in a cold frame. Stand the seed pot in shallow water to keep it wet. Move seedlings into pots once they are large enough to handle. Keep them in the cold frame through their first winter. Plant them out in late spring. Division offers another way to raise new plants. Divide in spring or autumn, then plant the pieces in place.

Plants For A Future lists leaves as edible and describes cooked young plants in soups. It gives edibility a low score of one out of five. Its account urges caution but gives no direct toxicity finding for this species. It lists no known medicinal or other uses. The supplied evidence names no pests or diseases. Plants For A Future does not flag it as weedy.