Repotting guide

When & how to repot Ludwigia palustris (Ludwigia palustris)

Also called marsh purslane, water purslane.

More about ludwigia palustris

About Ludwigia palustris

Ludwigia palustris · also called marsh purslane, water purslane · tropical

Ludwigia palustris is a hardy stem plant for aquariums and paludariums, prized for olive-green to bronze-red foliage that deepens under strong light and CO2. It grows fast both submersed and emersed, tolerates a wide temperature range, and is a classic beginner red-stem. Trim and replant tops to keep it bushy and colourful.

Mature size: Submersed stems reach 20-50 cm tall; emersed it stays low and creeping at 10-30 cm, spreading indefinitely.

How to tell ludwigia palustris needs repotting

Repotting on a calendar is less reliable than reading the plant. For ludwigia palustris, watch for these signs:

Roots poking out of the drainage holes or coiling visibly around the inside of the pot.
You are watering far more often than you used to because the rootball dries out within a day or two.
Water runs straight through and out the bottom without soaking in.
Top growth has slowed or new ludwigia palustris leaves are noticeably smaller than older ones despite good light.

For the underlying biology of a pot-bound root system and why it stalls a plant, see our guide to spotting and fixing a root-bound plant.

How often to repot ludwigia palustris

Every 12–18 months — sooner if roots show fast. Ludwigia palustris's growth habit — fast-growing, creeping-to-erect aquatic stem plant that sends out lateral side-shoots and roots readily at submerged nodes, forming dense bushes or mats. — sets the pace. Ludwigia palustris is a hardy stem plant for aquariums and paludariums, prized for olive-green to bronze-red foliage that deepens under strong light and CO2. It grows fast both submersed and emersed, tolerates a wide temperature range, and is a classic beginner red-stem. Trim and replant tops to keep it bushy and colourful.

What size pot to step ludwigia palustris up to

Step up one pot size — about 2–3 cm (an inch) wider. Ludwigia palustris grows fast, so it will fill that space within a season, but jumping several sizes at once still backfires: the unused soil stays soggy and rots even a vigorous root system. One size at a time, every year or so, is the rhythm.

Not sure of the exact diameter? Our pot size calculator takes the current pot and root spread and tells you the right next size — it deliberately recommends a single step up, never a big jump.

The best time of year to repot ludwigia palustris

Early spring, just as new growth restarts, is the ideal window for ludwigia palustris. The plant is moving into its strongest growth phase and re-roots into fresh soil quickly. Avoid repotting in winter dormancy or, for flowering plants, while it is in bud or bloom — recovery is slowest then and you risk dropping the flowers.

Step-by-step: repotting ludwigia palustris

Time it for spring. Repot ludwigia palustris in early spring as growth restarts so it re-roots quickly into the fresh soil.
Choose one size up. Pick a pot about 2–3 cm wider with drainage holes. One step only — a much bigger pot stays soggy and rots roots.
Ease the plant out. Water lightly the day before, then tip ludwigia palustris out and gently loosen any roots circling the bottom of the rootball.
Repot at the same depth. Put a layer of fresh nutrient-rich aquatic substrate in the new pot, set the plant so its soil line is unchanged, and backfill, firming lightly.
Water and pause feeding. Water once to settle the soil. Hold off fertiliser for about a month — fresh mix already has nutrients and feeding now burns new roots.

Aftercare

Water ludwigia palustris once to settle the soil, then let the surface dry before watering again — fresh mix around the roots stays wetter than the old compacted ball, so the commonest post-repot mistake is overwatering. Keep it out of direct sun for a week or two while roots re-establish. Do not fertilise for about 4 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for ludwigia palustris

Ludwigia palustris wants nutrient-rich aquatic substrate. Thrives in fine aquasoil or sand capped over nutrient base; benefits from root tabs as it is a heavy root feeder. Emersed, use a peaty, constantly wet loam in a bog or pond margin. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting ludwigia palustris — frequently asked questions

How often should you repot ludwigia palustris?

Every 12–18 months — sooner if roots show fast for ludwigia palustris. Repot ludwigia palustris roughly every 12–18 months, in early spring as growth restarts. It grows fast and circles its pot quickly, so step up one size (about 2–3 cm wider) into fresh nutrient-rich aquatic substrate. Don't jump several sizes — that soggy excess soil is what rots vigorous roots.

What size pot does ludwigia palustris need?

When is the best time of year to repot ludwigia palustris?

Can you put ludwigia palustris straight into a much bigger pot?

No. Even a fast-growing ludwigia palustris should only go up one pot size at a time. A vastly oversized pot holds a reservoir of wet soil the roots cannot reach, which stays cold and soggy and rots the roots — the opposite of what you wanted.

Should you fertilise ludwigia palustris after repotting?

Not immediately. Wait about 4 weeks after repotting ludwigia palustris. Fresh mix already contains nutrients, and feeding freshly cut or disturbed roots burns them. Resume your normal feeding routine once you see new growth.