Download Water Hyacinth

June 2011
Water Hyacinth
Eichhornia crassipes
WHAT IS IT?
A free-floating perennial aquatic plant
forming dense mats of vegetation on the
water surface
It is one of the world's worst weeds,
particularly in slow-flowing or stagnant
freshwater
Widely cultivated as an ornamental plant
Also known as: lilac devil, Nile lily, bèo
tây, bèo lộc bình, bèo nhật ban, po piu,
dai soy ping, pickerelweed, water orchid,
jacinthe d’aeu, mbekambekairanga, lirio
acuatico, jacinto de agua, floating water
hyacinth
Synonyms: Eichhornia speciosa,
Pontederia crassipes, Piaropus crassipes,
Piaropus mesomelas, Heteranthera
formosa
Water Hyacinth. “Forest & Kim Starr” www.hear.org.
WHY IS IT A PROBLEM?
Dense mats rapidly block and choke water
bodies, which:
increase loss of water through
transpiration
reduce water quality as rotting vegetation
depletes oxygen and fouls the water
alter or destroy natural wetlands and
habitat for aquatic fauna by reducing light
levels, temperature and oxygen
limit access by stock and wildlife to water
provide a breeding ground for diseasecarrying insects
interfere with recreational activities (e.g.
boating) and irrigation systems
Water Hyacinth Infestation choking waterway. “Forest & Kim Starr”, www.hear.org.
What are State Alert Weeds?
These are invasive weeds that are not known to be in South Australia, or if present, occur in low numbers or in a restricted
locality. If present in this State, they can reasonably be expected to be eradicated. An Alert Weed would pose a serious
threat to the State’s primary industries, natural environments or human health if it became established here. All Alert Weeds
are declared under the Natural Resources Management Act 2004: this means that sale and transport is prohibited
(Sect. 175 and 177); if found anywhere in this State their presence must be notified (Sect. 180) – refer overleaf, and plants
must be destroyed (Sect. 182).
DESCRIPTION
An aquatic herb 30-65 cm high, free-floating but sometimes attached to the
substrate underwater. It has black to purple feather roots that trail in the water.
It has glossy green, thick flat leaves that radiate from the base to form a rosette,
some with a swollen buoyant base to the leaf stalks. Flowers are a showy
bluish-purple colour with a distinctive yellow blotch on the upper petal, on a short
erect stem.
HOW IT SPREADS
Water Hyacinth. Habit showing feathery roots I&
swollen base. “Forest & Kim Starr” www.hear.org.
It reproduces by waterborne plant parts and seed. Plants form roots at the
nodes, which break away and form dense mats, and drift downstream forming
new colonies. This process is aided by the buoyant leaf bases, with leaves also
acting as sails. Growth from a single plant can cover 60 m 2 in one season.
Waterborne seeds are dispersed by birds and vehicles, movement of mud and
boating activities which can carry plant material through waterways.
HABITAT
Water hyacinth prefers still or slow-flowing water, including rivers, swamps,
reservoirs and farm dams. It prefers and proliferates in nutrient-rich, subtropical
and tropical conditions but will survive colder conditions including occasional
light frosts. It is killed by saltwater.
ORIGIN
Native to the Amazon Basin in South America (north-eastern Brazil, French
Guiana, Guyana, Surinam and Venezuela), it is now introduced and widespread
as an aquatic weed throughout warm freshwaters of the world.
DISTRIBUTION IN AUSTRALIA
Water Hyacinth introduced via ornamental use in
water features. “Forest & Kim Starr” www.hear.org.
Current: Naturalised mainly in NSW and Queensland, but also recorded from
Western Australia and Victoria. A serious outbreak occurred on the River
Murray in South Australia due to deliberate release at Ramco Lagoon in 1939,
but was eradicated in the 1950s once modern herbicides had been developed.
Potential: Water hyacinth could grow anywhere in South Australia where a
permanent body of static or slow-moving fresh water exists. It is a threat mainly
to the River Murray system where it could occupy backwaters and billabongs.
HOW IT GOT HERE
Deliberately introduced into Australia around 1894 as an ornamental plant for
garden ponds, and eventually discarded into waterways. Almost every
infestation in southern Australia has resulted from deliberate planting or disposal
of unwanted plants readily sourced from the aquatic trade.
DISTRIBUTION
Current distribution based on herbarium
records
Potential distribution based on climate
modelling
WHAT CAN YOU DO?
Be on the alert for this plant using this Fact Sheet as a guide. If you see a
suspicious plant that may be this State Alert Weed, please report it to your local
Natural Resources Management (NRM) Board (contact details at
www.nrm.sa.gov.au).
For more information on weeds, including Alerts,
contact your local NRM Board or visit either www.pir.sa.gov.au/biosecurity
(phone 08 8303 9620) or www.weeds.org.au.
Disclaimer: This publication is provided for the purpose of disseminating information relating to scientific and technical
matters. The Government of South Australia does not accept liability for any loss and/or damage, including financial
loss, resulting from the reliance upon any information, advice or recommendations contained in this publication. The
contents of this publication should not necessarily be taken to represent the views of the participating organisations.