Repotting guide

When & how to repot Inflated Bladderwort (Utricularia inflata)

Also called Floating Bladderwort, Swollen Bladderwort.

More about inflated bladderwort

About Inflated Bladderwort

Utricularia inflata · also called Floating Bladderwort, Swollen Bladderwort · tropical

Utricularia inflata is a robust free-floating carnivorous aquatic native to the eastern United States, recognisable by its distinctive inflated float structure that supports the flowering scape above the water surface. Bladder traps capture aquatic invertebrates. It needs soft, low-nutrient acidic water and full sun to bright light. Non-toxic to pets.

Mature size: Floating mat can cover 30-100 cm of water surface; flower scapes reach 10-20 cm above water

How to tell inflated bladderwort needs repotting

Repotting on a calendar is less reliable than reading the plant. For inflated bladderwort, 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 inflated bladderwort 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 inflated bladderwort

Every 12–18 months — sooner if roots show fast. Inflated Bladderwort's growth habit — free-floating aquatic annual or short-lived perennial with whorled filamentous stems and distinctive inflated float — sets the pace. Utricularia inflata is a robust free-floating carnivorous aquatic native to the eastern United States, recognisable by its distinctive inflated float structure that supports the flowering scape above the water surface. Bladder traps capture aquatic invertebrates. It needs soft, low-nutrient acidic water and full sun to bright light. Non-toxic to pets.

What size pot to step inflated bladderwort up to

Step up one pot size — about 2–3 cm (an inch) wider. Inflated Bladderwort 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 inflated bladderwort

Early spring, just as new growth restarts, is the ideal window for inflated bladderwort. 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 inflated bladderwort

Time it for spring. Repot inflated bladderwort 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 inflated bladderwort out and gently loosen any roots circling the bottom of the rootball.
Repot at the same depth. Put a layer of fresh no soil — free-floating in open water or over a peat-sand base 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 inflated bladderwort 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 inflated bladderwort

Inflated Bladderwort wants no soil — free-floating in open water or over a peat-sand base. Fully aquatic. If anchoring lightly, use an inert substrate such as washed acid sand. Avoid fertilised aquatic substrates or added nutrients in the water. Always use fresh mix when you repot — reusing old, broken-down soil reintroduces the compaction and poor drainage you are repotting to fix.

Repotting inflated bladderwort — frequently asked questions

How often should you repot inflated bladderwort?

Every 12–18 months — sooner if roots show fast for inflated bladderwort. Repot inflated bladderwort 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 no soil — free-floating in open water or over a peat-sand base. Don't jump several sizes — that soggy excess soil is what rots vigorous roots.

What size pot does inflated bladderwort need?

When is the best time of year to repot inflated bladderwort?

Can you put inflated bladderwort straight into a much bigger pot?

No. Even a fast-growing inflated bladderwort 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 inflated bladderwort after repotting?

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