Propagating Utricularia gibba (Humped Bladderwort)

How to propagate humped bladderwort, a rootless free-floating carnivorous plant, by dividing its tangled stolon mat, plus tips to keep this fast grower from turning weedy.

Overview

Utricularia gibba, the humped bladderwort, is a small mat-forming aquatic carnivorous plant. It has no true roots and either floats freely or sprawls over the substrate, forming mats of criss-crossing, branching, thread-like stolons up to about 20 cm long.

Along these stolons sit tiny ovoid bladder traps, 1–2.5 mm long, that vacuum in microscopic prey when their trigger appendages are touched. In favourable conditions the plant sends erect inflorescences above the water and produces yellow flowers throughout the year.

Propagation Method

Because the plant grows as a continuous stolon network, propagation is simply fragmentation and division of the stolon mat. There are no roots to disturb and no cut stems to root — any healthy length of stolon will continue growing on its own.

Step-by-Step

Lift or scoop out a portion of the floating tangle of stolons.
Pull or snip the mat into smaller sections, each with several centimetres of intact, green stolon.
Float each section in the new container or refugium; no anchoring is needed.
Provide bright light and soft, low-nutrient water, and let the fragments resume branching.

Conditions for Healthy Growth

In the wild U. gibba lives in ponds, ditches, pools, bogs and marshes whose water is poor in available phosphorus and nitrogen. It grows happily floating in a small cup or bowl, in waterlogged peat, or among water-filled trays, with only minimal requirements.

Soft, slightly acidic, low-nutrient water suits it best.
Provide medium to bright lighting to keep growth dense and green.
No substrate or CO2 is required for the plant to thrive.

Maintenance

Thin the mat regularly by removing handfuls of stolon, which both controls spread and gives you ready-made propagation fragments. Removed material can be discarded or used to start new containers.

Common Challenges

The main challenge is its weediness: the same fast, fragment-friendly growth that makes propagation trivial lets it smother slower plants. Keeping nutrients low and thinning often is the simplest way to keep it in balance.