Petaluma looking at alternatives to Roundup weed killer
Both the city of Petaluma and the area’s largest school district have largely suspended the use of a common yet increasingly controversial herbicide while evaluating the effectiveness of various alternatives, following an outpouring of public concern.
City parks staff and their counterparts at Petaluma City Schools said they have spent several months experimenting with products marketed as a more natural option than glyphosate-based weed killers like Roundup, which both said was in use only on a limited basis across their grounds. Applying the herbicide has been a standard practice for decades, but has come under fire in recent years by some groups who argue it comes at a cost to public health and the environment.
The ongoing trial has already offered up some complex considerations in Petaluma, ranging from the significantly higher cost of the alternative herbicides to the increased frequency of their use.
“We’re not under a moratorium, but we’re doing this internally so we can have some data to bring to people to consider,” said Ron DeNicola, parks and landscape manager for the city of Petaluma.
Swapping notes with some other cities that have sought alternatives to glyphosate-based weed killers, Petaluma parks staff switched to using so-called herbicidal soaps in March.
While glyphosate kills the root of the weed, the new products, under the brands Finalsan and Suppress, use naturally occurring fatty acids that damage the exposed part of the plant.
Petaluma City Schools is also experimenting with Suppress, as well as another brand called Avenger, said Joe DeCarlo, the district’s director of maintenance. The district has long avoided using glyphosate at elementary schools.
“We’re not entirely happy, we’re not entirely unhappy” with the products, said DeCarlo, who began the informal trial after hearing from a handful of community members concerned over herbicide use “about five or six months ago.”
Petaluma’s Recreation, Parks and Music Commission fielded similar testimony during a meeting in January, when a group of area residents expressed their concern over the city’s use of glyphosate-based herbicides. The city stopped using those herbicides while starting their trial in March, though DeNicola noted that a contractor who maintains landscaping in Petaluma’s medians still uses a glyphosate-based weed killer.
“At that point, I thought, why don’t we just be proactive and try some alternative products and see how well they work?” he said.
Among the clearest differences is the price - a 140-gallon mix of Roundup and water costs $62, while a similar mix of Finalsan, which requires more of the product in the mixture, costs $1,136, DeNicola said. A mixture of Suppress requires around half of the volume of product but, since it is pricer, costs $1,001.
Having used the alternative herbicides over the past two months, DeNicola said crews have needed to apply the treatments more often to achieve similar results. The plants are also likely to regrow, since the root remains alive underground.
The treatments are also said to be extremely pungent during application, with several workers complaining of eye irritation and one experiencing respiratory problems, DeNicola said. Those attributes have required the use of new protective equipment, something that was not required with Roundup.
“It’s frustrating being out there using something labeled as organic, but you have to be out there in a bodysuit and a respirator,” he said.
It’s not the first time Petaluma has experimented with alternatives to glyphosate - several years ago, the city also used citrus oil, clove oil and industrial-strength vinegar on an experimental basis. Yet weed and pest control chemicals are under tight federal regulations, and only approved herbicides, including those currently under trial in Petaluma, are allowed as part of an ongoing maintenance program, DeNicola said.
Members of Petaluma’s Parks Commission recently toured several sites where staff have been using the treatments, seeing first-hand how the trial is playing out in the real world.
Councilwoman Kathy Miller, who currently serves as a liaison to the commission, noted that the method seemed to show mixed results. Areas where mulch was applied after herbicide use seemed devoid of weeds, while the treatment appeared less effective in areas where weeds emerged from cracks in concrete.
“I know people don’t want to use Roundup – I don’t really want to use Roundup, either,” said Miller, who described her usage of vinegar to control weeds along the walkway in front of her home. “I’d love to hear if there’s an alternative that doesn’t break the bank, and that actually kills the plant.”