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Eichhornia azurea

Description
 

Anchored Water Hyacinth (Eichhornia azurea) is a mat-forming perennial (long lived) aquatic plant typically rooted in mud. Vegetative stems elongate, growing up to and at the water surface, with leaves above and below the water. Leaves below the water, or in heavily shaded areas, are linear, about 6-20 cm long and 0.5-1 cm wide, stalkless, with a blunt tip and alternately arranged in two rows on the stem. The leaves above the water are rounded, 5-16 cm long and 2-16 cm wide, with a slender stalk. Flowering stems are upright and 8-12 cm above the water. The flower is a spike with several flowers along a hairy stem. The flowers are funnel-shaped with six toothed petals each 1-3 cm long. The flowers are mostly lavender blue or white with deep purple centres. The uppermost petal has a distinct yellow spot (Scher undated). Individual flowers are open for one day only (Johnson undated). The fruit is a capsule with numerous seeds. The seeds are oblong to narrowly oblong in outline, measuring 1.5-2.6 mm long, 0.3-0.9 mm wide and thick, with about 10 longitudinal ridges or membranous wings evenly spaced around them (Scher undated).

For further information and assistance with identification of Anchored Water Hyacinth, contact the herbarium in your state or territory.

Distribution:

Anchored Water Hyacinth is not known to occur in Australia. It is a Class 1 declared pest plant in Queensland and a Class 1 noxious weed throughout New South Wales. As a notifiable weed in New South Wales, all outbreaks must be reported to the local council (Johnson undated).

Habit:Aquatic
Key points:

  • Anchored Water Hyacinth (Eichhornia azurea) is a mat-forming perennial aquatic plant typically rooted in mud.
  • It occurs in wetlands and irrigation channels, and in mud along rivers, lakes, marshes and canals.
  • It is native to Central and South America and does not yet occur in Australia.
  • Due to the worldwide weed status of Anchored Water Hyacinth, and its close relative Water Hyacinth (E. crassipes), species of Eichhornia have been designated as prohibited imports in various countries, including Australia.
  • Prevention of the establishment of Anchored Water Hyacinth is the best form of control.

How it spreads:

Anchored Water Hyacinth is able to spread when part of the plant breaks away, moves downstream and new daughter plants are produced. Whole plants, stem fragments, capsules and seeds can be carried by water, in mud, on vehicles and by birds (Johnson undated; Scher undated). Humans contribute to dispersal by growing Anchored Water Hyacinth as an ornamental plant in ponds and aquaria and by the careless disposal of plants or plant fragments and seed (Parsons & Cuthbertson 2001).

Where it grows:

Anchored Water Hyacinth occurs in wetlands and irrigation channels, and in mud along rivers, lakes, marshes and canals (Johnson undated; Scher undated). It can be rooted in mud or clay to a depth of 10-15 metres in water courses and dams (Johnson undated).

Flower colour:

Blue, White, Purple

Distribution map: Unknown
Impacts:

Along with other aquatic plants, Anchored Water Hyacinth forms floating masses that obstruct navigation (Scher undated). It smothers the surface of creeks, lakes and other water bodies (Jordan 2007).

Its potential impact is similar to that of Water Hyacinth (Eichhornia crassipes) which obstructs waterways, interferes with irrigation systems and hydro-electric generation, removes oxygen from the water thereby reducing fish production, harbours mosquitoes and other vectors of disease, reduces areas available for waterbirds and causes significant water loss due to transpiration where there are dense infestations (Parsons & Cuthbertson 2001).

Anchored Water Hyacinth is closely related to Water Hyacinth which is considered one of the world's most serious aquatic weeds and is a declared noxious weed in many countries. Due to the weed status of Water Hyacinth and Anchored Water Hyacinth, several, and in some cases, all species of Eichhornia have been subsequently designated as prohibited imports in various countries, including Australia (Winterton & Scher 2007).

Origin:

Anchored Water Hyacinth is native to Mexico, Central America, South America and Jamaica (Scher undated).

History:

Anchored Water Hyacinth is not known to occur in Australia (Johnson undated).

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This database is designed to provide information, including biological and ecological, on invasive plant species that are on a national weed list, or are legislated against in a state or territory. While reasonable efforts have been made to ensure the accuracy of the information, no guarantee is given, nor responsibility taken, by the Commonwealth for its accuracy, currency or completeness. The Commonwealth does not accept any responsibility for any loss or damage that may be occasioned directly or indirectly through the use of, or reliance on, the information contained in this database. The information contained in this database does not necessarily represent the views of the Commonwealth. This database is not intended to be a complete source of information on the matters it deals with. For further information on the images contained in the database please contact the copyright owner. All images in the weed identification tool are managed by the Australian Plant Image Index (APII). Various copyright conditions apply for these images. For further information on the copyright conditions of images contained in the database please contact the APII at: photo@anbg.gov.au.