Stem injection delivers herbicide directly into the hollow cane of the plant. Injections are made in the lower portion of the plant in the first few nodes above the ground. This method dramatically increases the translocation ability of the herbicide throughout the plants root system and is key to controlling invasive species with large rhizome structures. With this method there is no need to cut canes, or handle viable plant material for disposal. Canes too small to inject can be injected upon secondary follow up visit.
When? Injections can be made anytime during the growing season.
What to use?
Glyphosate is the primary herbicide for use in control of knotweeds. An Active Solution of at least 41% Glyphosate is required. Many Stores carry Glyphosate at lower percentage active ingredient, but for stem injection you need greater than 41%.
Imazapyr is also effective at 6mls per cane. Operators must be aware of risks to cross-root transfer of the herbicide. Because knotweed creates a monoculture this risk is low. Most knotweed stands will not have any other plants growing under their canopy.
PRODUCTS (USA): Aquamaster. Rodeo. Imazapyr. Roundup Super Concentrate. Polaris
Why inject below the third node for Japanese Knotweed?
If plants were injected above the third nodes only the upper portion of the canes will be affected. The rhizome structure will survive to propagate.
