There are two main ways to deal with established Japanese knotweed: treat it with herbicide over time, or physically dig it out. Both work when done properly, but they suit very different circumstances. Understanding the trade-offs will help you make the right call for your property.

Herbicide treatment

A professional herbicide programme involves applying the right chemical, at the right strength, at the right point in the plant’s growth cycle, over two to three growing seasons. Its big advantages are cost and minimal disruption. Your garden stays largely intact, and the price is usually a fraction of excavation. The trade-off is time: the plant is brought under control gradually rather than removed overnight, and the area needs monitoring to confirm success.

Excavation

Japanese Knotweed crown and rhizome being hand picked during the screening process

Excavation means digging out the rhizome and either removing it to a licensed facility or burying it on site under controlled conditions. Its great strength is speed. The visible problem can be gone in days, which is why it is often the right choice for development sites or sales that cannot wait. The downsides are cost, which is considerably higher, and disruption, as it is a major earth-moving operation that can affect lawns, paving and planting.

How to choose

As a rough guide, herbicide tends to suit homeowners who are staying put and are not under time pressure, while excavation suits those who need the ground clear quickly, such as builders, developers or sellers on a tight timeline. In some cases a combination works best. The right answer depends on your site, your plans and your budget, which is exactly what a survey is for. Our cost guide sets out typical figures for each.

Both can come with a guarantee

Whichever route you take, the work can be backed by a ten-year insurance-backed guarantee, which matters if a mortgage is involved. See our survey and guarantee page.

Get a recommendation

We will always recommend the method that genuinely fits your situation, not the most expensive one. Call 07518 456090 or book a call-back to discuss your options.