This is a question that I wish we received more often. While Round-Up (Glyphosate) is a great product and simple to use for a variety of vegetation management projects, we have seen many homeowners use these products incorrectly and cause damage ranging from mild to very extensive.
It should be stated that you should ALWAYS READ THE LABEL of any pesticide. It not only explains how, where, and when to use, but THE LABEL IS THE LAW. Allow me to repeat that since it is so important–The label on a pesticide has the full force of the law behind it. These labels are carefully written and approved by the EPA for safe use when used according to the label.
When choosing a vegetation control product, the active ingredients are easy to read on the front of the product and essential to correctly completing the task at hand. Here are some ingredients you will see:
Glyphosate: This is “original” or “regular” round up. This will kill (almost) all vegetation but will not prevent future growth of weeds and/or grasses. DO NOT SPRAY IN DESIRED GRASS AREAS. We see this all too often. You do not want your yard to have a brown polka dot pattern!
Diquat dibromide: This is an acidic ingredient used to make the treated areas “burn down” more quickly. This is mostly for marketing purposes. It makes the roundup work quickly and satisfies an impatient applicator.
Pelargonic acid: Similar to diquat, only faster. This can work within hours. Nifty, but not necessary.
Imazapic: Found in Round-Up Extended Control, this prevents new growth for up to 3-4 months. Generally safe, but this product can move (leach) within the soil and cause damage to grass and some shrubs and even mature trees. Because the product can move, it can cause damage in areas not intended to be treated. Use this with caution and not uphill from desired grass, tender plants or under certain trees such as linden, cherry, ash.
Imazapyr: CAUTION!!!! This is the ingredient we see cause terrible damage. This is found in products such as “Groundclear”. While a great product that can prevent growth for up to 1 year, it can also kill full grown trees with very little volume. This pesticide is considered a “soil sterilant” and will cause terrible damage in beds and can even kill mature trees.
On the other hand, when used correctly, it is wonderful in maintaining a bare-ground area for up to an entire season with just one application.
Remember: READ THE LABEL. And when in doubt, contact a professional to help with even the simplest projects. A short phone call can save you from a terrible mistake.