Last week, I was invited to the launch of Parks for London Integrated Weed Management guidance in Brixton, South London. Parks for London is an independent charity that aims to help the managers of London parks and green spaces to share knowledge, and manage resources in the best way possible.

The launch was a great opportunity to discuss with managers of green spaces in various London boroughs, such as Lambeth, which are phasing out glyphosate use in 2021, Sutton, which contributed significantly to the development of the guidance or Hackney, which is trialling no-spray zones. The presentations of the day are available on the Parks for London website.

There is growing public concern regarding the use of pesticides, and calls by politicians of all sides to reduce and even eliminate the use of pesticides such as the herbicide glyphosate in green spaces. The Plant Protection Products (Sustainable Use) Regulations 2012 aims to reduce “the risks and impacts of pesticide use on human health and the environment and promoting the use of… alternative approaches or techniques such as non-chemical alternatives to pesticides.” In July 2019, the London Assembly called on the Mayor to cease the use of glyphosate on Greater London Authority (GLA) land and the Transport for London (TfL) estate. On March 11, 2020, the Mayor Sadiq Khan committed to phase out glyphosate use on TFL and GLA land if he is re-elected.

As a result, the managers of green spaces have to find alternative ways of dealing with “unwanted” plants. Integrated weed management (IWM), an approach also used in agriculture, is the control of weeds through a long-term management approach, using a mix of techniques (manual removal, chemicals, biological control – such as the use of insects, and cultural controls such as mulches).

The policy template created by Parks for London is designed to help Local Authorities, but also other organisations that manage parks to develop a IWM plan. The associated reference guide, that provides a wealth of information to help develop a plan, is licenced (if you are interested do have a look at the dedicated Parks for London page as you may wish to gain access to the document). The document is divided into several sections, and offers useful decision trees such as this one:

In many cases as part of the IWM approach, like-for-like approaches to glyphosate such as manual weeding, flame guns or foamstream are used as they require the least investment. But over a long period of time, they are not always the most cost-efficient, and although they do solve the issue of chemicals going into the environment, they still impact biodiversity negatively, by reducing the amount of resources available to insects and other urban fauna.

I was pleased to see that the Parks for London template contains the following mentions: “The objective is to use chemical herbicides as a last resort and only when there are no other cost-effective or reasonable alternatives.”, “The toleration of weeds or the use of non-chemical methods for the control or eradication of weeds will always be considered first to ensure that chemical methods are only used where necessary.”

It is probably one of the first time that I have seen the “toleration of weeds” suggested, and it feels to me like a sign of changing times.

However, as rightly pointed out by Bill Wyatt, Technical Services Manager for the London Borough of Sutton, “the biggest area using herbicides is highway footpaths not parks“. Will “toleration” of weeds on footpaths increase in the future as here in Hackney? I certainly hope so…

2 thoughts on “Changing times…a guidance on “weed” management

  1. This is step forwards, and I like the idea of streets being able to opt out. However the unqualified statement that if left, weeds will damage the pavement is unfortunate. It is only the woody species this applies to – perhaps the annuals, the ones that are small and have flowers, could be left.
    I thought the IMP would be interesting to read. But not interesting enough to pay for it.

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    1. Yes, a lot of botanical education is needed at council level, and I will be working on this, slowly… I feel there is an opportunity to seize as maintenance and planning are increasingly taken back in house. As you say very rightly, only woody species and a few perennials such as those with taproots can lift pavements. Where I live in London, pavements are lifted but it is due to cars parking on kerbs, and trees, but weeds are often blamed without reason! The glyphosate ban in France has led many councils to plan pavement repairs with a reflection on urban flora – for example, the use of tarmac with strips of soil on the side to allow plant growth.

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