Ludwidgia longifolia - leaves and flower

Longleaf willow primrose

Ludwigia longifolia
Introduced to Australia as a garden ornamental and first recorded as naturalised near Sydney in 1991. Capable of producing up to 2.5 million seed per plant and 10 million seeds per square meter.
Family: Onagraceae
Origin: South America from Brazil to Argentina
Habit: Spring/Summer growing, woody, perennial, single stemmed or multi branched, erect, shrub ranging from 0.5m to 2.5m tall. Red, narrow, angular stems with unusual wing like characteristics.
Leaves: Simple, dark green linear to lanceolate/oblanceolate, up to 15cm long and 2.5cm wide, reducing in size up the stem.
Flowers: Solitary, 40-50mm across with 4 yellow petals, prominently ribbed, found in the junction of leaves and stems. Summer-winter.
Fruit and Seeds: Sharply 4 angled, oblong to narrow oblong 10-40mm long, 4-8mm wide. Unripe - green to red/green with prominent triangular sepals. Ripe - brown, papery and desiccated each containing around 7000 sawdust-like seeds.
Roots: Stout taproot and dense lateral roots.
Dispersal: Vegetation and seed spread by water, wind, animals, birds, humans, contaminated soil, earth moving machinery and garden refuse dumping.
Control: Hand dig/pull juvenile plants and remove as stems readily grow from cuttings, Scrape and Paint, foliar spray. No chemicals are registered for use on this plant, but an off label permit (7344) is available for spraying biactive Glyphosate. Contact your local weed officer.
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