The mesquite tree, often honey mesquite (Prosopis glandulosa), is a woody plant native to arid and semi-arid regions that has become an aggressive, invasive species. It thrives in harsh environments due to an extensive root system, including a deep taproot that reaches water tables far below the surface. This drought tolerance and ability to rapidly colonize grazing lands make removal challenging. Cutting the trunk at ground level stimulates vigorous resprouting from dormant buds in the root crown, often creating a dense, multi-stemmed shrub. Effective removal requires targeted methods that either physically extract the entire root crown or chemically kill the root system to prevent this aggressive regrowth.
Mechanical Removal of Established Trees
Mechanical removal is a non-chemical method that offers immediate, permanent results by physically extracting the entire plant, but it requires specialized equipment. This technique, often called grubbing, uses heavy machinery, such as excavators or bulldozers fitted with a specialized blade, to remove the root crown. The goal is to get beneath the bud zone, which extends several inches below the soil line, ensuring no regenerative tissue remains.
Cutting the trunk without removing the root crown stimulates coppicing, where the tree rapidly sends up multiple new stems, worsening the problem. For established trees, the first 10 to 12 inches below ground level must be removed to achieve permanent kill. Grubbing is most effective when the soil is moist, allowing the root ball to be extracted cleanly. This method is favored for large-scale clearing projects where the initial cost is offset by a high success rate against mature mesquite.
Cut-Stump Herbicide Treatment
The cut-stump method is a highly effective chemical approach for established mesquite trees, typically those with trunks greater than 6 inches in diameter. This technique involves severing the trunk and immediately applying a concentrated herbicide mixture directly to the freshly cut surface. The goal is to ensure the systemic herbicide is absorbed by the cambium layer, the thin, living tissue located just inside the bark.
The herbicide must be applied within minutes of cutting, ideally within 30 to 60 minutes, before the plant seals off the vascular tissues and prevents absorption. Common herbicides include oil-soluble triclopyr ester (15% to 25% concentration) mixed with basal oil or diesel fuel, or concentrated water-soluble picloram or glyphosate. Application during late summer or fall, when the plant translocates carbohydrates downward, enhances the herbicide’s effectiveness. Personal protective equipment must be worn during the mixing and application of these concentrated chemicals.
Basal Bark Herbicide Application
The basal bark application is a chemical control method best suited for smaller mesquite trees and saplings, generally those with a trunk diameter less than 4 to 6 inches. This technique avoids cutting the tree, instead relying on an oil carrier to penetrate the bark and deliver the herbicide to the vascular system. The process involves thoroughly wetting the entire circumference of the lower 12 to 18 inches of the trunk, including the root collar area.
The active ingredient is typically oil-soluble triclopyr ester, mixed with a commercial basal oil at a concentration of 10% to 30%. The oil carrier is necessary for the herbicide to pass through the waxy outer layer of the bark. This method is highly selective, minimizing damage to surrounding vegetation, and can be applied almost year-round. Complete coverage is essential; the solution should saturate the bark without excessive runoff onto the soil.
Long-Term Management and Seedling Control
Removing established mesquite is only the first step in a long-term management strategy because the plant’s seeds are persistent. Mesquite seeds can remain viable in the soil for decades, and new seedlings will emerge after mature trees are removed. Livestock and wildlife, particularly cattle, consume mesquite pods and disperse viable seeds across the landscape in their fecal droppings, aiding germination.
Controlling this new generation of seedlings is necessary to prevent re-infestation. Young mesquite plants are most vulnerable and can be managed with small-scale spot spraying of a suitable herbicide, such as a water-soluble triclopyr product, once they have developed true leaves. Alternatively, mechanical methods like repeated mowing or hand-pulling are effective for very young seedlings, provided the cut or pull is made below the cotyledons (seed leaves). Landowners should commit to annual monitoring and follow-up treatments, as continuous effort is required for long-term management.