Both the property in Miramichi and the one in Lakeville had a colony of Mexican Bamboo (or Japanese Knotweed). It’s a fast growing invasive species that is capable of killing off most vegetation that does not grow taller than it does.
I succeeded in killing it off on both properties. In both cases, it took 5 years. When I looked out of the window on our second viewing and saw it in front of the house, I chuckled. Having done it twice before I knew I could do it again & how long it was going to take.
When I was working away at it in Miramichi I did some Internet research. I found a site that explained why it was so difficult to kill off. The roots are brittle and are prone to breaking. The root system of the growing plants emit a chemical into the soil. So long as the chemical balance of the soil contains a certain level of the chemical, the broken off pieces of root remain dormant.
My guess is that the broken off roots only have a shelf life of a few years. If they don’t grow within 2-4 years they die. That means that if you can keep it from extending it’s root system for 3-4 years, the remaining roots in the soil die.
Even though the growing season is over, I got a head start on next year. The old stocks get in the way of cutting it back the next year’s growth. It doesn’t hurt that it improves the street view of the house.