Invasive water plant spreads in Richmond
Pretty parrot’s feather chokes out local flora, ‘clogs up water flow’
Richmond is being overrun by parrot’s feather, a particularly quickgrowing, invasive aquatic plant that’s been spreading thick and fast for years after being dumped by owners of aquariums or spread from backyard ponds into the city’s waterways.
And the pretty, bright green plant that is carpeting the ditches, canals and ponds in the city, as well as other municipalities of Metro Vancouver, is choking out local plants, killing fish and amphibians as well as blocking drainage of water to the Fraser River.
“It definitely clogs up the water flow,” said Richmond’s environmental co-ordinator Taryn Hesketh.
“If we weren’t doing anything about it, it would create more problems with drainage” and possibly flooding.
But the plant, like other aquatic invasives, is particularly challenging to eradicate because there are no approved herbicides for such plants in waterways and the plant is spread by a small piece of it being carried through the water or by frogs and birds. Herbicides are also ineffective because of the plant’s waxy surface, which repels chemicals, said Hesketh.
“Because of how easily it spreads, we have to ensure we’re removing it completely,” she said.
In areas where people have manually pulled them up or tried to smother the plants with special plastic liners, the results have been short-lived.
Last year, “the city spent on average $40,000 to contain further spread of the species (vs. eradication) to other areas of the city’s drainage system,” said Richmond city spokeswoman Kim Decker.
Parrot’s feather, which looks like a small fir tree, roots itself in the bed of waterways and grows to the surface of the water, forming a dense mat on the surface. When disturbed, a piece as small as four millimetres can float, be blown or carried downstream and eventually root.
“In some places, the growth is so dense you can’t see the water and you think you could walk over it,” said Tasha Murray of the Invasive Species Council of Metro Vancouver.
Richmond has drawn up an invasive species active plan to come up with a way to control infestations, including mechanical removal, geotextile installation and shading techniques (the plants don’t grow in areas of waterways shaded by trees), according to Richmond city’s website.
The plant, native to South America, has spread to all continents except Antarctica. In the United Kingdom, people have carefully pulled out the plants one by one with the help of volunteers, “but it’s very labour intensive,” said Hesketh.
While Ontario has banned the plant from that province, there is no law against parrot’s feather, a popular aquarium and garden decorative plant.
In B.C., the strategy to limit its spread is through education and awareness. Experts say the word has to get out to pet shops, garden stores and boat owners who are encouraged to “clean, drain and dry” their boats before moving from one water body to another. May is invasive plants awareness month and the councils are planning education campaigns.
“Let’s not buy it or plant it anymore,” said Gail Wallin of the Invasive Species Council of B.C.
She said parrot’s feather, which has been reported in Pitt Meadows and Burnaby and may be in other areas where it hasn’t been reported yet, affects how the public can use their waterways.
Wallin said the same problem exists with a similar plant called Eurasian milfoil in the Okanagan. And the plants are just one of many aquatic and terrestrial species that are invading the province, including English ivy, Brazilian aloeda, purple strife and yellow flag iris.
She agreed more education and awareness is needed, noting 60 per cent of samples of plants purchased at several garden and pet shops recently turned out to be parrot’s feather, even though they were labelled differently.
Van Dusen Botanical Garden in Vancouver said its policy since 2007 has been to not sell any invasive plants, and it screens all plants offered for sale at its annual plant sale, said spokeswoman Emily Schultz.