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The product label of the herbicide you are using
An online video tutorial produced by King County
Guidance from your local weed control program
Advice from Uncle Larry


Imazapyr
Triclopyr
2, 4-D
Glyphosate


Bohemian
Himalayan
Giant
Japanese


Glyphosate is the active ingredient
The type of site where you will be applying the herbicide is listed on the product label
The label contains instructions for hollow stem injection
All of the above


Shorts and a tank top
Coveralls and a face mask
A hazmat suit
It will be listed on the label of the product you are using


As early in the growing season as possible
Late in the growing season, but before the first frost
After the first hard freeze, when the plant has gone dormant


None
25%
50%
75%


Water
The herbicide you will be treating with
Rubbing alcohol
Lemonade


The top-most internode on the plant
Internodes around waist-height
The second or third internode from the ground
Knotweed doesn’t have internodes


The injector needle splits the stem wide open
The stem is smaller than your pinky finger
The internodes look too small to hold the injected dose of herbicide
All of the above


All appropriately sized stems
Every third stem of knotweed
One stem per clump of knotweed
One stem per ten square feet of knotweed


All appropriately sized stems
Dump the remainder in a nearby creek
Distribute over your newly landscaped lawn
Consult the label for appropriate disposal


Once
Twice
Three times
None, you’re too tired from injecting weeds to care


Your name
The time it took you to complete treatment
The approximate square footage treated
The approximate location of the area treated
All of the above

Related information

Related agencies


Program offices are located at 201 S. Jackson St., Suite 600, Seattle, WA 98104. To contact staff, see the Noxious Weed Control Program Directory, send an email, or call 206-477-WEED (206-477-9333).