Glyphosate [N-(phosphonomethyl) glycine] is the main ingredient in Roundup and similar herbicide products.
Generally speaking, when you apply a product containing glyphosate, you can expect to see gradual yellowing and wilting of the offending plants’ leaves over the next few days, but in some cases, it may take as long as three weeks.
Information found on Roundup’s website indicates that most of their products designed for use on weeds and unwanted grasses will show some results within a few hours.
However, those designed against more stubborn plants (e.g., tough perennial weeds) may take as long as 12 hours to start working.
Be sure to carefully read the labels of any glyphosate-containing product you are considering. For best results and safety, always follow directions closely.
Roundup & Glyphosate Q&A
1. How long has glyphosate been in use?
The chemical was developed in the 1970s and has been widely used worldwide