Last December, the London Borough of Croydon became the latest local authority to announce an end to the use of glyphosate in parks in 2019, following examples set by others.
Hammersmith & Fulham, for example, became the first council in London to halt the use of herbicide sprays in parks and open spaces in June 2016 to trial chemical-free weedkillers. Hackney followed suit in 2018.
Croydon did not comment, but its move follows a US court case four months ago that led to Monsanto being told to pay a groundskeeper $289m damages after he claimed the herbicide caused his cancer.
However, the Crop Protection Association has put the cost of banning low-cost glyphosate by councils for amenity use at £228m. Glyphosate is licensed in the EC until 2022.
If some local authorities are rethinking their weed-treatment regimes, so too are some contractors. G Burley & Sons based in Dorking, Surrey, has for some clients switched techniques to Weedingtech’s Foamstream that uses hot water and a biodegradable foam made from natural plant oils and sugars.
Contracts manager Mark Tavener says his company is looking to expand its reach and is in talks with Brighton & Hove City Council and a water company, both of whom approached G Burley & Sons, which is finalising start dates.
The Monsanto court case threw the spotlight on weed control. "It's had a big impact on the industry and public perception," says Tavener. "We still get cynics who think our method is gimmicky and costly, but the vast majority of the public are immensely supportive when we explain what the apparatus is about and that the product is chemical-free." That apparatus includes big hot-water tanks mounted on the back of vans and long hoses for good coverage.
Although glyphosate is "cheap as chips", he reckons demand for his alternative approach will double in the next two years thanks to growing awareness from councils such as Croydon. Currently the new technology is about 20-30% more expensive per square metre than glyphosate. But as customer numbers increase, the product will become more cost-effective per square metre or per day, he forecasts.
Foamstream is easier to use than conventional products because users do not need spraying certificates, he adds. The only downsides are the tanks are cumbersome and application requires more than a knapsack — coverage is about 85% against glyphosate's 95%.
Ground Control national group training manager Neil Huck is yet to be convinced on the alternatives to glyphosate — and neither does he believe Croydon's decision will trigger a mass movement. When he explains to his clients why, many choose to stay with the tried-and-tested chemical, he says. This is partly because of the legal position of glyphosate. It has approval from the Chemicals Regulation Division, Defra and the EU until 2022.
Also, the scientific evidence on links to cancer has been questioned. The Monsanto case, for example, hinged on a report that also said wine and coffee could be "potential" threats, says Huck. "When we explain the science we find most of our clients are happy to stay with glyphosate. Apart from being more expensive, alternatives give off emissions from diesel trucks and use energy for steam or hot water, both of which can pose safety risks. This issue has become political, not logical, but I don't think Croydon will mark a sea change."
Nevertheless, Huck is to undertake trials of hot water, steam, foam, fire and citric acid systems as well as wire brush and even manual weeding to ensure clients can make more informed decisions. A crucial question is: "What level of weed growth is acceptable to the community?", says Huck, because this can influence weeding regimes and regularity.
This is just the kind of advice Amenity Forum independent chair John Moverley will bring to local authorities in London this spring when he is due to host a joint event with Parks for London to spell out the facts and blow the myths on the use of glyphosate. "I'm neither for nor against, and it's not the job of the forum to take sides," he says. "But there is lots of emotive language and strong lobbying against glyphosate. Perhaps a good middle path is to minimise, and optimise, use and also blend in cultural methods such as a proper brushing regime."
Another method is electric. English Heritage recently adopted the RootWave Pro as its main method of weed control at Audley End House & Gardens, Essex, after two years of trials. The tech is also used to spot weed and treat invasives in France, Canada, Jersey, New Zealand and South Korea.
Chief executive Andrew Diprose says the EU is funding him to trial an agricultural system for vegetable growers that can identify weeds and zap them with an electrical circuit in the leaf and roots. The system is organic, does not disturb soil and will be cost comparable with using herbicides, he says.
"Alternative treatments are not perfect and we can't go head-to-head with the big companies. But systems like electricity can complement traditional methods. Reducing use of chemicals is not just good for the environment but cuts the risk of overusing chemicals leading to weed resistance."