Leafy Creek Farm Blog: How to remove mesquite organically

How to remove mesquite trees organically: Pulling Mesquite in September 2020 (updated January 2024):

If you have mesquite invading your pasture, you will share our respect for this worthy antagonist. Armed with sharp thorns that drive away cattle and a very strong and long taproot that resists anything but direct assault, this tree has a survival mode that causes it to return even bigger and stronger after its branches are cut off. The only way to remove it without using poisons is to remove the rootball.

Here we document our method for removing small and medium sized mesquite trees. We hope others will find this useful because when we started, we could not find detailed information on how to remove them. This discussion does not apply to large mesquite, which have trunks more than say 6 inches or so in diameter. For these, a bulldozer may be needed but see section on medium-sized trees in case that might help.

Removing small (up to 4 inches diameter) mesquite trees by pulling

The overview is:
  • Look at the tree to figure out where the taproot is likely to be. If it is small, perhaps a foot or two high, and has a single stalk, that is where to start. Once the tree reaches medium size, about 2-3 feet high or more, it usually has at least two branches that emerge separately from the soil. In that case, the taproot is likely midway between two branches and at the rough center of multiple branches.
  • Using a shovel after a recent rain (or pouring water over the ground and waiting), start about a foot away from the center of the tree and dig a funnel-shaped hole around where the taproot seems to be. You can exert a lot of force with the shovel against the tree: it is very strong!. Put the dirt off to one side in a small pile so you can replace it later. You may be able to keep the vegetation on top separate so you can put it on top when you refill the hole.
  • Look for roots coming off the side of the tree as you dig. Once you see these, you have reached the rootball. There should be no more branches rising above the ground once you have reached this level. If the tree is small, the side roots will be tiny. However, if the tree is 4 to 6 feet or so high, the side roots can be an inch in diameter. Clip these roots as you find them so that you can continue to dig deeper.
  • Continue digging until you have found a number of side roots. At this point, you have to assess the best way to remove the rootball. If the tree is small or on the small side of moderate, the diameter of the rootball will be getting smaller as you dig deeper, and you will be able to wiggle the tree easily. In this case, you can clip the tree at the bottom of the hole and fill it in. If it is really tiny (say up to about a foot high above the ground) and the ground is moist, often you can simply pull the taproot out by hand. Often this taproot will be longer than the above-ground portion of the tree.

    On the other hand, if you find that the rootball is several inches in diameter, the side roots are an inch in diameter, and the rootball is not getting smaller even though you have dug down a foot or so, it is time to pull the rootball with your tractor. For this, you need something to grab the rootball firmly and something to attach that tool to your tractor safely. (Legal notice: this article describes what we do and does not make recommendations. You are responsible for the safety of what you do.)

    We use the Brush Grubber BG-12 Grubber to attach to the rootball. This hinged tool has two plates, one on each arm, with very strong teeth that bite into the sides of the rootball. The hinge causes the plates to press more tightly against the rootball when a tugging force is applied to the hinge. There are several fine points to using the Grubber. First, it is very hard to hold open unless you place it on the ground resting on the hinge, and pull the arms apart. Once they are fully apart, you can hold them open with one hand so you can place it carefully around the rootball. Second, the length of the teeth is just enough to bite in to the wood after penetrating the bark. If the plates have crud on them left over the last use, the crud will prevent the teeth from biting into the wood and you may find yourself just stripping away bark. Removing the crud solves this. Third, only the rootball is strong: the upper part of the tree (that is, above the ground level) is not. If you use the Grubber on a branch, the odds are that you will just rip off the top of the tree.

    We use a tow strap rated for 15 tons to attach to the Grubber to the tow hitch on the back of our 100 HP tractor. The reason is that you do not want the strip to break under tension. If that happens, the end attached to the tractor could snap back into the cab and hurt you. We figured that the tractor weighs about 4 tons so the wheels should slip before it generates 15 tons of horizontal force.

    Once the Grubber is placed around the rootball and a test tug by hand shows that it does not slip, we drop the other end of the tow strap around the tractor's tow hitch, place the tractor's transmission in the lowest gear, raise the engine speed to 1600-2000 RPM (revolutions per minute), and slowly move the tractor forward. We do this in two stages: very slowly to settle the teeth of the Grubber into the rootball, and then slowly and steadily to apply force to the Grubber. Typically, there will be a slight pause and then the rootball will slip out with up to 10 feet or so of side roots. In one case of a largish medium tree, 1600 RPM did not dislodge the tree but 2000 RPM did. The reason to start very slowly is that if the Grubber does not attach firmly, it will simply slip off the tree and slide on the ground, and you do not want to be accelerating the tractor under power with no resistance.

    To dislodge the Grubber from the tree, it helps to wiggle it around and to press one of its arms against the ground while pulling on the other, but ultimately you will have great respect for the force required to remove this able opponent from your pasture!

Removing medium-sized (more than 4 inches to maybe 6 inches diameter, including with multiple branches) mesquite trees by mechanical disruption

Mesquite trees can grow quite large. We have some that are dozens of feet high that arise from a single trunk that is several feet in diameter. We have not tried to remove these and suspect that a bulldozer would be necessary.

But we did remove several trees that had many large branches each, with each branch up to about 4 inches in diameter. The rootballs of these trees were about 12 inches in diameter, and could not be pulled out. Here we describe how these were removed after breaking off the branches by pushing with an implement attached to a tractor or skid/track steer.

The following describes our results using a Case TR310B track steer with a grubbing attachment made by I Dig Texas in Marble Falls, TX.

We had three root balls about a foot in diameter each that remained after breaking off all the branches. Each had had multiple branches, suggesting that prior attempts to kill the rootballs had been made. Using upward force with the grubber was completely ineffective: the high-pressure interlock on the track steer simply halted the machine, and pushing caused the tracks to spin. Pushing down around each rootball to break the side roots had no apparent effect. Trying to saw the rootball with a chainsaw yield some cutting but mostly dulled the chain's blades.

The successful strategy was mechanical disruption using the edge of the grubber, oriented vertically, combined with the weight of the track steer, which was applied by pushing down with the front end loader and moving the tracks forward slightly so that the track steer rose up while supported by the edge of the grubber. Then, the grubber was rotated slightly up (ie, forward), which caused the rootball to break slightly. This process was then repeated until the rootball was disrupted. The side roots remained, but were small enough (only 1-2 inches in diameter) to cut with clippers or a chain saw.

This method should be applicable even to larger rootballs because the force is directed to the sides of the ball, not straight up. The taproot, which is very effective at resisting upward force, does not protect against sideways forces, and forces in this direction can destroy the rootball from the top down.