Understanding Herbicides

Herbicides help control unwanted plants, and in some cases, they can be the only solution to eradicating and controlling invasive vegetation. You don’t have to be a chemist to understand the various herbicides available, but what you use depends on what you’re trying to accomplish. Get the facts below.

Herbicides fall into two general categories:

  1. Selective: herbicides that kill specific varieties of plants. They are a fantastic tool for clearing weeds out of food plots and for removing unwanted invasive plants in wildlife habitat.
  2. Non-selective: herbicides that kill all plants it contacts. It’s the most common tool for carving out new food plots, and it’s an important one for starting fresh in existing food plots. Glyphosate, the active ingredient in Roundup, is commonly used.

Read the label

Reading the label will help you understand the various uses for the herbicide, but often times, it tells you the exact plants it controls and what plants it’s safe to use on.

Labels also provide safety instructions and application rates, usually in terms of ounces per acre or ounces per gallon, to prevent you from doing more harm than good.

Herbicide terms

Pre-emergent: used before seeds sprout. Pre-emergents can only be used after desired plants are established.

Post-emergent: used to control plants after they have started to grow

Systemic herbicide: kills the entire plant, roots and all

Contact herbicide: kills only the parts of the plant the herbicide contacts

Nonselective herbicide: kills all plants it comes in contact with

Selective herbicide: kills only those plants noted on the label

Restricted herbicide: available only to licensed applicators

Unrestricted herbicide: available to anyone

Be patient and safe

It can take weeks to notice any impact of some herbicides. Just because the plant doesn’t look like it’s dying a week or two after you sprayed doesn’t mean the herbicide isn't working. Follow instructions on the label and give it time.

Handle all herbicides with care and know they can be dangerous to you and harmful to the environment if handled improperly.

If you have more questions, contact your local cooperative extension agency.

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