- Widespread. In Australia, and most Pacific island countries.
- Annual, or perennial, fast-growing, invasive weed of wetlands - streams, ponds, marshes, swamps, ditches. Weed of rice, taro, cocoa, coconut and sugarcane plantations, pastures, along roadsides. Roots grow from lower nodes and extensive mats develop.
- Stems hairy, green, reddish-brown, up to 3m, sometimes woody at base. Leaves, alternate, pear-shaped to oval (up to 15cm), hairy, short stalks. Flowers, terminal or from leaf axils, with four yellow, oval petals (10-20mm long), with leaf-like sepals beneath. Fruits long (20-45mm), brown, ribbed with sepals attached, containing many seeds.
- Spread: vegetatively on creeping stems that root; seed, possibly in water, or in mud on machinery/vehicles, footwear. Plant trade: used as an ornamental and in traditional medicines.
- Biosecurity: risk is unofficial introduction of seed and plants. Available on Internet. Check imported machinery/vehicles.
- Biocontrol: none.
- Cultural control: hand-weed; slashing; mulch (5-10cm) to prevent seedling growth; clean soil and seeds from machinery/vehicles; check clothing.
- Chemical control: In Australia, glyphosate registered as spot-spray for other Ludwigia species in semi-aquatic and aquatic situations. In Fiji, glyphosate, 2,4-D, dicamba, MCPA.
