The Best Way to Kill Underbrush

Cut Large Undergrowth

• Cut back larger undergrowth to open stalks and trunks so that glyphosate herbicide will be more effective. A saw, ax, pruners or brush blade on a gas trimmer will cut underbrush and should be used based on comfort level and personal preference. Cut the brush within a few inches of the ground if possible, as this will also help to knock down larger brush and provide immediate visual results to the area.

Mix Glyphosate

• Glyphosate is a systemic herbicide widely used in government, private, commercial and residential grass, weed and brush control. The proper mixture rate for glyphosate will differ depending on whether the herbicide is applied to growing stems, branches and leaves or cut stumps. Make a 50 percent concentration of glyphosate when applying to cut stumps. Mix 60 ounces of glyphosate with 1 gallon of water in a spray tank. For spraying growing vegetation, make a 10 percent mixture by adding 13 ounces of glyphosate to 1 gallon of water in a spray tank. For both mixtures, place the top on the tank and shake to mix the water and glyphosate thoroughly.

Spray Herbicide on Underbush

• Spray the 10 percent mixture of glyphosate on underbrush when the plants are actively growing. Look for new growth, blooms and fruit production on the underbrush as signs that the plants are actively growing. Underbrush that is producing new growth, blooms or fruit will more readily absorb the herbicide sprayed onto the foliage and stems than when it begins to go dormant for the winter. Apply the glyphosate to coat the leaves and stems but not to the point of runoff. Adjusting the hose end nozzle on the spray tank to a wide spray will help to cover more of the underbrush surface area.

Apply Herbicide to Cut Stumps and Stalks

• The stronger 50 percent glyphosate mixture is used to treat cut stumps and stalks of larger-growing underbrush. Adjusting the hose end nozzle on the spray tank to a fine stream will help direct the concentrated herbicide onto the stump or stalk. Thoroughly wet one stalk or stem at a time with the herbicide for good coverage.