Ludwigia repens · also called Creeping primrose-willow, Red ludwigia, Red repens
🐾 Pet-safe
Generally non-toxic to cats and dogs.
A robust, beginner-friendly red stem plant with oval leaves that range from green on top to deep red underneath. One of the easiest ways to add red coloration to a planted tank.
ℹ️
Educational only. KinStation content is reviewed by licensed veterinarians but cannot replace an in-person exam. Always consult a licensed veterinarian or board-certified specialist for diagnosis, treatment, or any decision affecting your pet's health.
Quick facts
Category
Aquatic Plants
Family
Onagraceae
Native origin
North and Central America (United States to Mexico)
Care difficulty
Beginner
Light
Medium light
Pet toxicity
Pet-safe
Light
Tolerates low to high light. Under low/medium light leaves are green with reddish undersides; under high light (40+ PAR) the whole plant turns rich red to burgundy. More light yields more compact, redder, bushier growth.
Water
Temperature 18-28 C (64-82 F), pH 6.0-8.0, soft to hard water (GH 3-15) — very tolerant. Benefits from water-column dosing of macros and micros; iron and good lighting bring out the strongest red color.
Soil & potting
A rooted stem plant (not an epiphyte). Roots into any substrate but grows fastest and reddest in nutrient-rich aquasoil or with root tabs added to inert gravel/sand. Plant individual stems into the substrate, spaced apart so light reaches lower leaves.
Environment — humidity, temperature, placement
CO2 is not required but improves growth rate, leaf size, and coloration. Best in the midground or background; group several stems for a bushy effect. Tolerates a range of flow. Grows both emersed and submersed; emersed forms have a more upright primrose-willow habit.
Propagation
Propagate by cutting and replanting tops; the cut base sprouts side shoots. Lateral shoots and trimmings root easily. Stems that fall and touch substrate will also root and form new plants.
Toxicity detail
Non-toxic and safe with fish, shrimp, and snails. Native to the Americas; note that the floating water-primrose relatives (Ludwigia peploides and L. grandiflora) are aggressive invasives banned/regulated in Europe and parts of the US — these are different plants from L. repens, but as a precaution never release any Ludwigia into the wild.
Growth stages
How this plant changes through its life — each stage often has its own care, diet and space needs.
Photo coming soon
Spore / recruit
Aquatic plants and macroalgae establish from spores, seeds, or drifting fragments that settle and attach to substrate or rock. Many freshwater aquarium plants and marine macroalgae also spread readily from a detached piece that takes root or holdfast.
Photo coming soon
Young growth
Young growth puts out its first blades, fronds, or leaves and anchors with roots or a holdfast. Submersed plants may look different from their emersed form, and growth speeds up as the plant adapts to the water's light and nutrients.
Mature
A mature aquatic plant or macroalga reaches its full size and characteristic shape, forming the dense growth, runners, or fronds typical of the species. Established plants spread to fill space and can be divided or trimmed to propagate.
Varieties & cultivars
Natural forms are the wild species; cultivars are selectively-bred colour or variegation forms of the same plant.
Natural forms1
Repens (green/red)
Common stem plant with green tops and reddish undersides, the colour shifting with light. The standard, easy form.
💡 Brighter light turns the whole plant redder; in low light it stays green with only red undersides.
Cultivars2
Rubin
Selected cultivar with intense ruby-red leaves top and bottom, a far deeper red than the standard repens.
💡 High light plus iron and CO2 are needed to hold the full ruby colour; otherwise it fades toward green-red.
Super Red (Ludwigia 'Super Red')
A closely related selection (often L. palustris/glandulosa 'super red') prized for staying vivid blood-red even under moderate conditions.
💡 Easier to keep red than most ludwigias, but bright light still gives the best colour.
