Ludwigia hyssopifolia aka Seedbox

Ludwigia hyssopifolia is in the evening primrose family, Onagraceae. Kew gives its native range as southern Mexico through tropical America. It also lists northern Australia as part of that range. Useful Tropical Plants gives a different view of its roots. It suggests Southeast Asia but says the first range is unclear. It also records the plant across tropical Africa and much of tropical Asia. The two accounts leave its native range in doubt.

The plant grows as an annual, living for one year. It can form a woody base as it grows. Kew also lists subshrub and shrub forms for this species. Useful Tropical Plants gives a height of about 4.9 feet [1.5 metres]. Its full account gives extremes of 0.16–9.8 feet [0.05–3 metres]. These heights do not confirm a range for garden plants. The text gives no leaf shape or full stem details. It does not describe the flowers or fruit. Nor does it say when the plant blooms.

This plant lives in wet parts of the tropics. It also grows in many places where people disturb the ground. It grows by pools, rivers, drains, and shallow ditches. It lives in rice paddies and damp gardens left fallow. Waste ground and clearings also give it a place to grow. As a pioneer plant, it can colonise old volcanic mud deposits. Records range from lowlands to about 3,281 feet [1,000 metres] above sea level. Wild plants grow on clay and damp white sand. These sites point to a need for moist or wet ground. The text gives no frost limits or light needs.

Useful Tropical Plants calls it a weed that spreads with ease. Its role as a paddy and garden weed outweighs any recorded value for show. The source says it grows from seed. It records self-pollination and self-fertility: the plant can pollinate itself and set seed. The text names no pests or plant diseases. It gives no garden spacing or width at full growth. Its weedy growth is the main growing problem reported here.

People gather wild plants for medicine and a black dye. They use the whole plant to make the dye. Folk remedies use it for diarrhoea, dysentery, and other bowel disorders. Poultices treat boils, pimples, and skin infections in these uses. People boil leaves in water to make decoctions for fever. They have also used cold root infusions for syphilis. These accounts record uses, not proof that the treatments work. The source reports no known food uses or hazards. This does not show that the plant is safe to eat.