Japanese knotweed is one of the most invasive plants in BC, and effective eradication takes time, strategy, and consistency. At Western Weed Control, one of the most frequent questions we are asked is: “How many treatments will it take to get rid of knotweed?” The answer depends on several factors, but here is what you need to know.
Typical Treatment Timeline: 1 to 3 Years
Eradicating Japanese knotweed usually requires a multi year plan, typically spanning 1- 3 years. The exact duration depends on factors such as:
- How long the knotweed has been established
- The size and spread of the infestation
- Soil quality and moisture levels
- Nearby structures, water sources, or ecological sensitivity
- Soil disruption
How Often Do You Need to Treat It
Typically, our approach involves 2-3 herbicide treatments per year, usually timed for maximum effectiveness during the plant’s growing cycle. Treatment is most effective to begin in June and continues through to October, when the plant is actively drawing nutrients into its root system. If you miss the June window, one treatment can also be effective in July or September depending on the establishment of the plant.
What Makes Treatment More Effective or Slower
Several factors influence how many treatments you may need:
- Severe infestations or plants near water sources may require longer, due to application restrictions
- If the knotweed is encroaching from a neighbour’s yard, and we do not have permission to treat their property, regrowth may occur
- Early intervention and consistent follow up increase the odds of eradication
- Leaving the area undisturbed
What About Safety and Environmental Impact
All herbicide applications are performed by trained technicians, and it is safe for pets to return to treated areas after the product has dried. We take great care to minimize off target damage to nearby vegetation.
Let’s Build Your Custom Treatment Plan
No two knotweed infestations are exactly alike. That is why Western Weed Control offers site specific treatment plans designed to maximize results. Whether you have spotted knotweed early or are dealing with an established problem, we are here to help.
Contact us today to get started on the path to eradication.
