Is ludwigia easy to grow in an aquarium? Yes. Aquarium ludwigia such as L. repens ‘Rubin’ and L. palustris ‘Super Red’ are easy red stem plants. Tropica rates both low in CO2 need, with medium growth to about 4–12 inches (10–30 cm) in two months. Strong light deepens the red. Pond species, the water primroses, are invasive, so buy carefully.
Key takeaway: Ludwigia gives aquariums easy red color. Grow L. repens or L. palustris under medium to strong light, trim often for bushy groups and replant the tops. Keep pond-type water primroses such as L. hexapetala and L. grandiflora out of outdoor water, because USGS links their spread to the ornamental trade.
| Species | Use | Key facts | Source |
|---|---|---|---|
| L. repens ‘Rubin’ | Aquarium | Dark red; medium light; low CO2; 8–12+ in (20–30+ cm) | Tropica |
| L. palustris ‘Super Red’ | Aquarium | Reddens easily; low light; low CO2; 4–12+ in (10–30+ cm) | Tropica |
| L. hexapetala | Invasive pond weed | Surface mats; spreads by fragments | USGS |
| L. grandiflora | Invasive pond weed | Large-flower primrose-willow | USGS |
What Is Ludwigia?
Ludwigia is a large genus of water and marsh plants called primrose-willows or water primroses. In aquariums, the common choices are cultivars of L. repens, a North American stem plant, and L. palustris, which Tropica describes as cosmopolitan. Outdoors, several floating and creeping species are serious weeds of ponds, ditches and lakes.
Knowing which one you are buying matters. The aquarium types stay small and manageable indoors; the pond types can cover water surfaces. Check the full botanical name on the label or receipt, and ask the seller if a pot is sold only as “water primrose.” Because USGS names the ornamental plant trade as the main pathway for L. hexapetala, assume pond stores may stock weedy species, and choose native or non-spreading marginal plants for outdoor water instead.
How Do You Grow Ludwigia in an Aquarium?
Grow aquarium ludwigia in groups under medium to strong light. Tropica says L. repens ‘Rubin’ has few demands, but if light is too low the lower leaves tend to fall off, and stronger light makes the color more intense. Plant stems a short distance apart in the gravel so light reaches each one.
- Remove any rock wool and lower leaves from new stems.
- Plant stems in a group in the midground or background.
- Give medium to strong light; see our aquarium grow light guide.
- Feed with a liquid fertilizer and root capsules near the group.
For feeding, read our guide to fertilizer for plants in water.
How Do You Make Ludwigia Turn Red?
Ludwigia turns red with strong light and, for best color, added CO2. Tropica says L. palustris ‘Super Red’ turns red more easily than ‘Rubin’ and becomes intensely red and grows better with good light and added CO2. Both still grow without injection, since Tropica rates their CO2 need as low. Green stems usually mean light is too weak.
- Raise light intensity or duration gradually.
- Add CO2 for deeper color; see our CO2 enrichment guide.
- Keep floating plants from shading the group.
How Do You Trim Ludwigia?
Trim these stems regularly to keep them bushy. Tropica says L. palustris forms side shoots on its own, but cutting increases them so the group becomes denser, and the cut tops quickly root when replanted. For ‘Rubin’, Tropica advises regular pruning in large groups. Cut above a leaf pair at a plant node.
- Cut stems that approach the surface.
- Replant the healthy tops beside the group.
- Pull out old, bare lower stems over time.
- Remove every loose fragment from the tank.
Which Ludwigia Species Are Invasive?
Water primroses such as L. hexapetala and L. grandiflora are invasive in parts of the US. USGS says the main introduction pathway for L. hexapetala is the ornamental plant trade, with stem fragments then carried by water and waterfowl. It forms dense surface mats that block sunlight, lower dissolved oxygen and reduce habitat for fish, waterfowl and turtles.
- USGS also profiles L. peploides, floating primrose-willow, and L. peruviana.
- L. hexapetala mostly spreads by stem fragments, per USGS.
- It tolerates full sun, water to about 3.3 feet (1 m) deep and many soil types.
USGS adds that seeds stay embedded in woody capsules and seedlings are rare, so fragments, not seeds, drive most of the spread. That is why a single stem tossed into a ditch matters. Never plant water primroses in a garden pond that drains to streams, and never dump aquarium trimmings outdoors.
Can Ludwigia Grow Out of Water?
Yes. USGS lists marshes, swamps and pond edges as habitat for the genus, and many species grow emersed along wet shores. In aquariums, stems that reach the surface may grow emersed leaves. Trim them back below the water to keep the plant compact and its submerged color strong. Emersed leaves are usually rounder and greener, so a sudden change in leaf shape near the surface is normal.
Does ludwigia need CO2?
No. Tropica rates both L. repens ‘Rubin’ and L. palustris ‘Super Red’ as low CO2 plants, though CO2 improves color.
Why is my ludwigia losing lower leaves?
Usually low light. Tropica says lower leaves of ‘Rubin’ tend to fall off when light is insufficient.
How tall does ludwigia grow?
About 8–12 inches (20–30 cm) for ‘Rubin’ and 4–12 inches (10–30 cm) for ‘Super Red’ after two months, per Tropica.
Is aquarium ludwigia invasive?
Treat every species as a release risk. Some pond species, like L. hexapetala, are invasive, per USGS.
How do you propagate ludwigia?
Cut the tops and replant them. Tropica says cut shoots of L. palustris root quickly.
Sources
- Tropica Aquarium Plants. Ludwigia repens ‘Rubin’/4450).
- Tropica Aquarium Plants. Ludwigia palustris ‘Super Red’/4453).
- USGS Nonindigenous Aquatic Species. Six petal water primrose (Ludwigia hexapetala) Species Profile.
- USGS Nonindigenous Aquatic Species. Large-flower primrose-willow (Ludwigia grandiflora) Species Profile.
- Photo credits (Wikimedia Commons, edited with titles): Ludwigia repens by Show_ryu (Public domain); Ludwigia at karakund 2 by Nativeplants garden (CC BY-SA 4.0); Planted Tank 03 – Flickr – The Wandering Angel by The Wandering Angel from Makati City, Philippines (CC BY 2.0); Rotala SN68AJG by Kk70088 (CC BY-SA 4.0)