Japanese knotweed
Reynoutria japonica
What is it?
Japanese knotweed looks like bamboo. It often grows to heights over 6 feet and in dense stands. It spreads via rhizomes—roots that shoot out deep and wide in the soil. This makes knotweed particularly hard to eradicate.
When to remove?
There is no bad time to remove this plant. However, removing it in the spring will help avoid growth in the summer, when it grows fastest. You should return to the removal site again in the fall to cut back any summer growth before the ground freezes. Plan on doing removals in the spring and fall for several years.
How to remove?
The best method for control is to cut the plant to the ground as many as three times a season. Following each cutting, cover the area with heavy-gauge black plastic film and mulch. Depriving the rhizomes of light is the only way to prevent their regeneration. When cutting the stalks, cut flush with the ground, leaving no protruding stumps. Be careful digging up this plant. Even the smallest bits of the root system that break off will form new plants.
How to dispose?
Discard the entire plant, roots and all, in sealed plastic garbage bags. Do not put it in with your yard waste. If you have large quantities, contact our office to coordinate pick up. Do not attempt to compost this plant. It will regenerate.