Ludwigia

Ludwigia is a genus of aquatic stem plants in the family Onagraceae, native primarily to North and South America. It is the quintessential genus of red aquatic plants in the hobby, with numerous species coloring from bright orange to deep crimson depending on light intensity, CO2 levels, and iron availability. Species range from beginner-friendly L. repens and L. palustris to the demanding L. super red, which requires high light and injected CO2 for its spectacular coloration. Strong illumination is the single most critical factor for red pigmentation; iron-rich liquid fertilizers further enhance the effect. Densely planted backgrounds of red Ludwigia create vivid color gradients that contrast strikingly against green planting, making this genus a staple in competition aquascaping.