For the last few years, the City of Burnaby has been waging a war against an enemy that isn’t so obvious.
Invasive plants have been the scourge of many Lower Mainland municipalities for some time, but recently, Burnaby has been getting the upper hand in the fight against them.
Since 2009, all invasive plants in treatment areas are showing reduced growth and spread, and in some cases, there has been no regrowth for more than two years, according to a recent report to the city’s environment committee updating Burnaby’s invasive species management plan.
Specifically, the city has made great strides against the knotweed species in the last few years.
The city began a herbicide treatment program in 2010 targeting the manual removal of the plant at 12 sites in six parks. But the manual efforts weren’t producing the results, so the city upped its game and began using a herbicide treatment in three parks. Treatments began with stem injection and expanded to include foliar spray of stems too small to be injected.
The staff report noted stem injection of the large stems were effective in killing portions of plants, but the small untreated stems continued to thrive.
With the combination of stem injection of large stems and foliar spray of smaller stems, where 100 per cent of any one infestation is treated, the results of herbicide treatment have improved greatly. The report said sites monitored in July and October 2015 found efficacy was at 95 to 100 per cent.
Dave Ellenwood, the city’s director or parks and recreation, said the results over the last few years are good news for Burnaby.
“We can’t eliminate them, but I think we’ve been successful in controlling invasive species,” he told the NOW, particularly noting the success in treating Japanese knotweed.
He also pointed out the success in educating the public on the issue, noting people now know what invasive species are and are helping the city in the fight.
Ellenwood suggested in future years, the city will stay the course with the invasive plant strategy, but added if it starts to get out of our control more resources will be used.
In the case of knotweed, the report said in 2016 all sites will be monitored for re-growth and retreated as necessary, and an expansion of foliar spray treatment will target infestations of smaller stems, in a timely manner.
“New sites will be added to the treatment based on budget and on a priority system based on importance of sightlines or public safety reasons and frequency of maintenance,” the report said.
In 2009, of the 1,786 hectares of park lands in Burnaby, approximately 1,484 hectares were surveyed, and approximately 284 or 19 per cent of the total area surveyed were impacted by invasive species.
