Following one of our in-depth surveys, we will select the best management plan depending on the extent of the infestation. To manage the spread of the weed on your land, our expert team will often employ a range of methods. One of these is Stem Injection Treatment.

Japanese Knotweed Herbicide Treatments

Method Two: Stem Injection

Timescale: 3-5 Growing Seasons

This is an excellent treatment option because it is low-impact and has little risk of disturbing the growth of other plants in the area. Stem injection is typically utilised for lesser infestations, especially where the Japanese Knotweed has established itself among attractive plants or near a watercourse that could become polluted if another treatment is used.

Using a stem injector, we inject an Environment Agency-approved herbicide into the lowest half of each mature Knotweed stem. Younger infestations may not be acceptable since the Knotweed plants must have thick enough stems for the pesticide injection to be effective. The stem-injection technique we utilise is particularly effective in dry or inclement weather, but the soil cannot be disturbed after the treatment. The stem injection approach is most successful from late summer to early fall, and it has the greatest impact when the plant is blossoming.

This process involves injecting a specified dose of undiluted herbicide directly into the stems of the plant, between the first and third ‘node’ of the stems. This process has the benefit of reducing the possibility of damaging non-target plants, however, this method is only suitable for smaller infestations and can take longer to administer compared with a foliar spray.

Benefits of stem injections include:

Cost-effective solution for getting rid of Knotweed

• Treatment can go ahead regardless of the weather
• Environmentally friendly with no negative effects on nearby plants or wildlife
• If a Tree Preservation Order is in place, stem injection is safe to use
• Ideal for use near water or on sensitive site

You should consider that herbicide treatments can present problems when you have plans to landscape the garden, extend the house or re-turf the lawn. Although effective, you are unable to dig or disturb the soil as it can spread the plants further and invalidate your guarantee.