Bladderwort species

Bladderwort is an algae-like perennial (sometimes annual for u. livida) aquatic herb.

Description

• Mat-forming and submerged just below the water surface.

• Stems are thin with filaments like leaves and bladders that trap insects and suck in prey when external hairs are triggered.

• Flowers are submerged, purple/white, and appear in summer.

• U. gibba flowers are yellow and held above water on stalks.

• Roots are absent.

• Seeds are small and ripen in summer-autumn. Dispersed by water movement.

• Habitats include still or slow-moving water bodies.

What you need to know

Bladderwort spreads aggressively and forms dense mats, threatening small turf-forming species and native bladderwort species in freshwater ecosystems. It may shade submerged vegetation and alter sediment chemistry.

Management approach

Bladderwort is declared an unwanted organism by the Ministry for Primary Industries (MPI) because it is capable of causing harm to the natural environment, physical resources or human health in Aotearoa/New Zealand.

These species pose a high risk to our environment, economy, recreation, and cultural values.

Rules

Any species declared a pest, including unwanted organisms, cannot be sold or be in a place where plants are being sold. Pest plants cannot be propagated, bred, or multiplied, communicated, released, or cause to be released, or otherwise spread.

Control

Do not attempt to undertake control of bladderwort yourself. Report any sightings to us.