The weed

• Aggressive, invasive, alien plant species that originated in Southern Africa, where it is regarded as a nuisance weed.
• The plant can grow in water up to 6m deep.
• In addition to occupying the full water column, plant stands produce dense vegetation on the water surface.
• The leaves are strongly recurved and are borne in whorls of 3 or in a spiral arrangement.
• The long stem is brittle and easily broken (aiding dispersal).
• Only female plants are present and all reproduction is by fragmentation or vegetative reproduction.
• Detached stems, when they sink, root from the nodes and establish new populations.

The Problem

• Currently, in Ireland, we are at an early stage in infestation; however, significant weed stands exist in Lough, Corrib.
• Forms very dense infestations in suitable habitats
• Capable of occupying the full water column inwaters up to 6m deep.
• Stems are easily broken and disperse rapidly.
• Dramatically alters the ecology for native plants, insects and fish
• Creates a poorer ecosystem for native plants, insects and fish
• Poses a serious threat for tourism, angling, boating and other recreational pursuits.
• Can cause fish kills through oxygen depletion
• Potentially a more major threat than the Zebra mussel.

The Cause

• Sold by garden centres as an oxygenating plant.
• Spread by fragmentation via wind dispersal, boat movement, angling equipment and, possibly, waterfowl.

Control

• An expert group with international experience in aquatic weed management has been convened to determine and implement all possible options for the control and elimination of Laragosiphon major.

The habitat

• The weed will grow in lakes rivers streams, canals and ponds.

To stop the spread

Do

• Always thoroughly clean your
  boat,
  trailer,
  engine,
  angling equipment
  and waders
  when leaving the waterway.

Don't

• Introduce any weed to any watercourse.
• Dispose of invasive plant material in the vicinity of any watercourse.
• Drive boats through established stands.

How can you help?

If you see this plant please immediately inform:

Dr. Joe Caffrey,
Central Fisheries Board.

Email: joe.caffrey@cfb.ie

This brochure was produced with assistance from the Western Regional Fisheries Board, the National Parks and Wildlife Service and Galway County Council.