Repotting guide

When & how to repot Common Nardoo (Marsilea drummondii)

Also called Common Nardoo, Nardoo, Australian Nardoo.

More about common nardoo

About Common Nardoo

Marsilea drummondii · also called Common Nardoo, Nardoo · houseplant

Common Nardoo is an Australian aquatic fern with distinctive four-lobed, clover-like fronds that float on still or slow-moving water. Grown in tubs or pond margins, it roots into submerged mud and tolerates both shallow water and periodically dry conditions. Best suited to warm climates; bring indoors in frost-prone areas. Historically a First Nations food plant when prepared correctly.

Mature size: Fronds to 20 cm (8 in) above the water surface; rhizomes spread indefinitely across soft substrate

How to tell common nardoo needs repotting

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

Roots creeping out of the drainage holes or matting tightly across the soil surface.
The rootball dries out within a day or two no matter how much you water.
Water channels straight down the gap between rootball and pot without wetting the centre.
Steady decline — thin growth, persistent crispy edges — that good humidity and watering have not fixed. Only then is the disturbance of a repot worth the risk for common nardoo.

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 common nardoo

Every 1–2 years, disturbing the roots as little as possible. Common Nardoo's growth habit — rhizomatous, creeping aquatic fern; fronds arise from a slender horizontal rhizome buried in mud and float or stand erect depending on water depth — sets the pace. Common Nardoo is an Australian aquatic fern with distinctive four-lobed, clover-like fronds that float on still or slow-moving water. Grown in tubs or pond margins, it roots into submerged mud and tolerates both shallow water and periodically dry conditions. Best suited to warm climates; bring indoors in frost-prone areas. Historically a First Nations food plant when prepared correctly.

What size pot to step common nardoo up to

Go up only one size and handle the rootball as little as possible. Common Nardoo resents root disturbance, so the goal is to slide the intact rootball into slightly more soil — not to tease, wash or prune the roots. A modest step up means less shock and a faster recovery.

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 common nardoo

Early spring, just as new growth restarts, is the ideal window for common nardoo. 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 common nardoo

Keep disturbance to a minimum. Common Nardoo resents root disturbance, so the plan is to move the intact rootball — not to wash, tease or prune the roots.
Choose just one size up. Pick a pot only one size larger with drainage, and have moisture-retentive heavy loam or clay aquatic substrate ready.
Slide the rootball out whole. Water the day before, then ease common nardoo out keeping the rootball intact. Gently free only the roots that are circling the very bottom.
Nestle it into fresh soil. Add a base layer of fresh mix, set the rootball in at the same depth, and backfill gently around the sides without packing hard.
Water and protect. Water in, then keep it warm, humid and out of direct sun for a few weeks while it re-roots. Expect a short sulk — that is normal.

Aftercare

Expect common nardoo to sulk for a couple of weeks — that is normal after any root disturbance for this group. Keep it warm, humid and out of direct sun, water just enough to keep the mix lightly moist, and do not panic and overwater while it re-roots. Do not fertilise for about 4 weeks — fresh mix already carries nutrients and feeding freshly disturbed roots scorches them.

The right soil mix for common nardoo

Common Nardoo wants heavy loam or clay aquatic substrate. Plant into heavy loam, clay, or proprietary aquatic basket compost — not lightweight peat-based mixes that float away. A basket filled with firm, fertile clay-loam topped with pea gravel to hold the substrate in place works well. No drainage layer needed; the entire root zone should stay wet. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting common nardoo — frequently asked questions

How often should you repot common nardoo?

Every 1–2 years, disturbing the roots as little as possible for common nardoo. Repot common nardoo every 1–2 years, disturbing the roots as little as possible — it sulks for weeks if the rootball is teased apart. Slide it into one size up in spring with fresh heavy loam or clay aquatic substrate, keep it warm and humid afterwards, and never bare-root or hard-prune the roots.

What size pot does common nardoo need?

When is the best time of year to repot common nardoo?

Why does common nardoo sulk after repotting?

Common Nardoo resents root disturbance, so a wilt or stall for a week or two after repotting is normal, not a failure. Minimise it by keeping the rootball intact, stepping up just one size, and keeping the plant warm, humid and out of direct sun while it re-roots.

Should you fertilise common nardoo after repotting?

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