Japanese Knotweed Identification

Not sure if you have Japanese Knotweed? Click here to contact us. Choose “Japanese Knotweed” from the “Services” drop down and then send us a picture. We’ll review it and follow up with you.

Japanese knotweed is highly invasive and can quickly spread through fragmentation, outcompeting native vegetation and causing damage to infrastructure and property. Its vigorous growth and extensive root system make it difficult to eradicate once established. The rhizomes of Japanese knotweed can penetrate deep into the soil, sometimes reaching depths of over 2 meters (6 feet).

Four species of invasive knotweeds are found in the Metro Vancouver region: Japanese knotweed, Bohemian knotweed, Giant knotweed, and Himalayan knotweed.

The eradication process varies significantly depending on factors such as the amount and location of the infestation. Typically, it spans 1-4 years. This timeframe is contingent upon various factors including the plant’s establishment, environmental conditions (such as location, soil quality, and weather), and the extent of disruption to the surrounding ecosystem. Our methods are optimized to achieve the shortest possible timeframe for eradication.

The most effective method typically involves applying herbicides 2-3 times annually. However, the approach may vary significantly from property to property depending on the extent of infestation. It might be necessary to employ a single treatment method or a combination of different methods. Given the variability of nature and timelines, our Japanese knotweed specialists are trained to consider all factors to achieve the best possible results.

For optimal results with spray treatments, the window of effectiveness typically falls between June and October.

Disturbing the ground after herbicide treatment can potentially spread Japanese knotweed fragments, leading to further infestation. It is recommended that the plant and soil are undisturbed to prevent re-establishment.

Physical removal of Japanese knotweed can be a fast and effective option, especially when combined with herbicide treatments. However, it is essential to seek our professional expertise to ensure removal is conducted effectively and safely.

Pulling or cutting the weed from the ground can stimulate the growth of Japanese knotweed. It is recommended to always leave the plant undisturbed during the growing season (April to October). In the winter months when the plant is dormant, you can cut the brown stems and dispose of them into the garbage.

During application of herbicide, please keep persons and pets out of the area. It is safe to enter the yard post-treatment. We advise allowing up to 12 hours for the herbicide to fully dry before permitting persons or pets to access the treated area.

Our skilled team employs techniques to minimize any harm to neighboring plants. However, it’s important to acknowledge that proximity to knotweed may present challenges in entirely avoiding off-target damage.

Dead stems should be disposed of in the regular garbage bin. It’s crucial not to dispose of them in compost, as this could potentially facilitate the spread of the invasive plant.

If the source of the knotweed is traced back to your neighbor’s yard, we’ll need their permission to administer treatments on their property. Untreated knotweed poses a persistent threat of spreading, but on your property, we can implement effective spray treatments to manage the invasion.

Yes, although we must maintain a minimum 1-meter distance from creeks and water bodies when applying treatments, as required by regulations.