The weeping willow tree is notoriously hardy and can survive numerous harsh conditions to grow back stronger than ever. While this survivability is an attribute if you are a weeping willow fan, the trees can also start to disrupt your yard and their root systems can interfere with the roots of other plants and trees nearby, and even underground utilities. In those instances, weeping willows are frustratingly difficult to get rid of. Killing a weeping willow requires some hard work and diligence to ensure it doesn't grow back.
Cut the weeping willow down with a chainsaw. You may wish to use a professional service for this to ensure the tree doesn't damage anything when it falls over. The service can also remove tree remnants. You want to get rid of the entire trunk and all the branches of the weeping willow and leave only the stump in your yard. If you cut the tree down yourself, use gloves, safety goggles and proper safety equipment.
Drill several holes into the top and the side of the stump and fill them with stump decomposer. The side holes should be drilled at 45-degree angles. The chemical agent in the decomposer will help kill the remaining stump and loosen it to make it easier to remove from the ground. Water the stump lightly and continue to add stump decomposer for the next four to six weeks in accordance with the chemical's instructions.
Fill the holes with kerosene after the stump is dried out. Once the kerosene has absorbed into the wood, pour a little more into a hole and carefully light it. The stump and the roots connected to it should gradually reduce to ash.
Check the local laws of your area to ensure you can legally burn the stump in your yard. If not, you will need to use a stump puller to remove it.