Public support needed to keep water free of banned weeds

The Ministry for Primary Industries (MPI) and Auckland Council are
asking residents to report any fresh sightings of two banned and
highly destructive weeds - water hyacinth and salvinia.

Both weeds are present in the Auckland region and are known for
growing rapidly to form large dense floating mats on ponds, drains,
lakes and still waters in swamps.

“Water hyacinth and salvinia are among the world’s worst
weeds,” says MPI Response Manager Emmanuel Yamoah.

Both plants grow very quickly. Water hyacinth is able to double its
population size in as little as 12 days, while salvinia only needs
about a week.

“These weeds have the potential to cause huge damage to our
waterways, native aquatic plants and fish. They can clog waterways,
making almost all water activities impossible and increasing the
danger of drowning to humans and livestock. The weeds also have
adverse impacts on hydro-electricity generation and irrigation.”

Dr Yamoah says MPI and the Auckland Council have an eradication
programme in place for water hyacinth and salvinia.

“We need to know where these weeds are so we can wipe them out, so
the assistance of the general public is crucial to the success of the
eradication programme.”

He says many home and farm ponds around Auckland have been cleared of
the noxious weeds, thanks to calls from concerned owners and
residents.

“Anyone who sees any of these weeds, or suspects they may be
present, should report it to us on 0800 80 99 66. MPI contractors
will visit the site and remove the weeds free of charge if they find
them.”

It is illegal under the Biosecurity Act 1993 to share, grow or sell
unwanted and notifiable organisms.

Background information about salvinia and water hyacinth

Salvinia is a small, free-floating aquatic fern with branched,
horizontal stems that lie just below the water surface. The upper
surface of the leaf is covered with distinct white hairs. It has a
root-like structure underneath each leaf pair and as the plant
matures, these ‘roots’ resemble wet hair. The plant grows usually
up to 30cm long.

Water hyacinth is a floating aquatic perennial, with distinctive
bladder-like swollen leaf petioles giving buoyancy. It has shiny
rounded leaves with thick masses of feathery dark roots that can
reach 2.5m in length. A single flowering stalk with a cluster of
mauve-blue flowers, each with a yellow spot, is produced above the
foliage. Plants produce floating horizontal stems from which new
plants arise.

Water hyacinth was first declared as a Class A noxious weed in 1981
under the Noxious Plants Act. Salvina was first declared in 1983.

Visit http://www.biosecurity.govt.nz/pests/salvinia
for more information.

Pictures of water hyacinth and salvinia are available on request.

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