To kill a cottonwood tree, destroy its stump, roots and sprouts. Purchase or rent a saw, shovel, gloves, goggles, a stump grinder, saltpeter and weed killing chemicals. Check with your state before you begin killing the tree to ensure it does not require a permit.
- Cut down the tree
Using a saw, cut down the cottonwood tree as close to the base of the stump as possible. Hire a professional tree removal company if you do not have experience cutting a tree down.
- Grind the stump
Wearing gloves and protective glasses or goggles, use a mechanical stump grinder to remove the remaining stump. Pick up the grindings and throw them away.
- Add saltpeter
Put saltpeter, a potassium nitrite compound used in gunpowder, on the area where the stump once stood. Drill holes in stumps that cannot be ground down, and fill them with saltpeter. Use saltpeter to starve and kill remaining roots, which are typically buried deep in the soil.
- Dig up sprouts
Look for sprouts that pop up after grinding down the stump. Use a shovel to dig the sprouts out of the ground and throw them away.
- Kill remaining sprouts
If sprouts continue to grow after the stump is removed, spray a chemical designed to kill weeds on the area. Reapply saltpeter and chemicals until the sprouts stop growing.