Lagarosiphon

• Aggressive perennial submersed aquatic plant with branched, brittle stems up to 5m long.
• Can grow surface-reaching mats of up to 4m from bottom of water body.
• Leaves are stiff, curled backwards, alternately arranged in spiral form.

• Inhabits still and slow-flowing water bodies.
• Prefers clear water due to high light requirements.
• In clear water, can live up to 6.5m below surface.
• Grows well on silty or sandy beds with low nutrient levels.

• Not known to occur in Queensland.

• Under suitable conditions, forms large, surface-reaching mats throughout the year.
• Male flowers break from plant and float towards female flowers, which remain attached to stem by long, thin, filament-like tube.
• Predominantly reproduces from stem fragments in native and introduced range.
• Flowering or regeneration by seed has not been observed in Australia.

Environmental

• Invades dams, lakes and streams.
• Affects native fish and waterbirds when growth becomes dense and restrictive.
• Out-competes native aquatic plants and forms mono-specific stands.

Economic

• Interferes with power generation and irrigation infrastructure by blocking intake systems.
• Interferes with recreational activities such as boating, fishing and swimming.

• Mainly spread by humans through boat trailers and fishing gear.
• Also spread by water movement: stems break at node, float downstream, produce new infestations.

• Find out how farmers can prevent weed spread.
• Find out how gardeners and outdoor enthusiasts can prevent weed spread.

• Before undertaking any preventative or control actions, contact our Customer Service Centre.
• Treat weed infestations when small.
• Remove underground stems and broken plant pieces to prevent regrowth.

Biological control

• No known biological control agents.

• Lagarosiphon is a prohibited invasive plant under the Biosecurity Act 2014.
• You must not keep, move, give away, sell or release into the environment. Penalties may apply.
• You must not take any action reasonably likely to exacerbate the biosecurity threat posed by lagarosiphon.
• You must take any action that is reasonably likely to minimise the biosecurity threat posed by lagarosiphon.
• You must report all sightings to Biosecurity Queensland within 24 hours.