With Japanese Knotweed an ongoing problem throughout public gardens at Quarry Bank Mill in Cheshire, the site’s head gardener has turned to Stem Injection Systems (Europe) for its treatment solution.

Quarry Bank Mill in Styal is one of Britain’s great industrial heritage sites, reflecting how a community lived throughout the Industrial Revolution in the late 1700’s. The National Trust acquired Quarry Bank House and its gardens in 2006 and then the gardener’s house and upper gardens in 2010. Along with the preserved textile mill, some 15 acres of gardens are now open to visitors throughout the year.

With various knotweed infestations throughout the grounds, the National Trust began using the stem injection treatment method when it acquired the gardens and, following her appointment as head gardener a couple of years ago, Sarah Witts has maintained this ongoing treatment programme.

Her main treatment work takes place at the height of the growing season in June with injection of a measured dose of glyphosate-based herbicide concentrate directly into the centre of each individual plant’s hollow cane. By late September, when it comes to the follow-up programme, most of these weeds will have died back and any that were missed in the initial treatment were then injected.

Sarah commented: “Having used the stem injection system in my previous job at Bodnant Garden, another National Trust property in North Wales, I was already familiar with this treatment technique, its ease of use and effectiveness.

“The National Trust obviously sets very high standards in terms of health and safety and sound environmental practices. With Japanese Knotweed scattered throughout the public gardens it is important to be able to localise the treatment programme, avoiding any impact on other plants and vegetation whilst also minimising inconvenience to our visitors.”

It is estimated that up to 80% of the Japanese Knotweed in Quarry Bank’s gardens has now been eliminated and that with a couple more stem injection treatment programmes the entire infestation could eventually be removed.