Broadly, there are two categories of weeds that pose more than an ‘untidy’ aesthetic issue for managers of school grounds.
- Invasive weeds would typically characterise species that are non-native; wild and rampant growers that seek to dominate any space around them. In the process, they upset the native natural ecosystem, destroying native flora and impoverishing the habitat of many native fauna.
Japanese knotweed, for example, is so persistent that it can exploit weaknesses in the foundations of buildings. Others can harm people: the sap of Giant hogweed (see main pic) contains chemicals which can cause human skin to become hyper-sensitive to sunlight, resulting in blistering, pigmentation and even persistent scarring.
Himalayan Balsam is another example of an invader, typically blanketing huge swathes of riverbank across the UK. Surprisingly, this category of undesirable species includes plants that many people consider an attractive asset in a garden, such as Buddleia and Rhododendron.
- Injurious weeds are technically categorised as those that harm agriculture – perhaps because they take nutrients out of the soil, constrain the growth of crops or are poisonous to farm animals. These include docks, thistles and ragwort.
Your obligations
There are no specific legal rules for schools on the management of invasive or injurious weeds, and it is not illegal to have such weeds on your campus. However, various statutes and best practice regarding its control and disposal, public and lender perception and your relationship with neighbouring landowners, combine to provide you with a moral and reputational imperative to control them.
Who can you call?
If it were a simple case of strim or squirt to manage them, these weeds would not pose quite the threat they do. Many of these plants are extremely persistent, with root systems that can remain viable after many years of dormancy, or 'violent' seed dispersal that is hard to counter. Professional advice should be sought as soon as possible to minimise the spread of these species, and to fulfil your duty of disclosure to your insurers as well as duty of care to the public.
Our resident ‘weed buster’, JPA founder Jeremy Peirce, is a qualified amenity agronomist with a specialism in invasive and injurious weeds. He is one of the few experts on the BASIS Professional Register located in the South West. He can work with you to advise the most effective treatment and ongoing management plans.
Click here to read his technical guide to dealing with Japanese knotweed >>>
And our guide to identifying Japanese knotweed >>>