Weeping willow trees are known for their rapid growth and graceful, drooping canopy, but their aggressive nature often necessitates permanent removal. This species is highly resilient, possessing an intense, water-seeking root system that can spread three times the width of the canopy, commonly damaging underground pipes and foundations. The tree’s persistent ability to sprout new growth makes complete eradication a challenging process. Permanently killing a weeping willow requires a targeted, two-pronged approach combining mechanical removal with the systemic application of herbicide to ensure the entire root structure is destroyed.
Necessary Preparations and Safety Checklist
Before initiating any mechanical or chemical action, it is important to first complete a thorough preparation and safety checklist. Begin by contacting the national “811” service or your local utility locators to mark the position of all underground lines, which is especially important given the willow’s invasive root structure. You should also check with local municipal or county offices to determine if a permit is required for removing a tree of a certain size or near a property line.
The timing of the operation significantly affects the effectiveness of the chemical treatment. Systemic herbicides are most effective when applied in late summer or early fall, which is when the tree naturally transports carbohydrates downward to its roots for winter storage. This downward flow, known as translocation, draws the poison deep into the root system, maximizing the kill rate. Safety precautions require wearing appropriate personal protective equipment, including chemical-resistant gloves, safety goggles, and long-sleeved clothing, when handling herbicides and power tools.
Targeted Mechanical and Chemical Treatment
The most reliable method for permanently killing a resilient willow tree involves a combination of cutting and immediate chemical application to the stump. First, the tree must be felled, leaving a stump as close to the ground as possible. Following the cut, the trunk’s vascular system, specifically the living layer just beneath the bark called the cambium and sapwood, must be treated immediately.
For larger stumps, apply the systemic herbicide directly to the outer ring of sapwood, which is the lighter-colored wood that transports nutrients. This application must be done within minutes of the cut, as the tree rapidly begins to seal the wound, significantly reducing the herbicide’s absorption. Common household weed killers are ineffective against a mature willow, necessitating a concentrated systemic herbicide such as glyphosate (at 20% concentration or higher) or triclopyr.
An alternative method is the “hack-and-squirt” or stem injection technique. This involves making downward-angled cuts, or “frill cuts,” with a hatchet or axe around the trunk’s circumference, penetrating the bark and cambium layer. Each cut should be spaced approximately two to three inches apart and immediately filled with the concentrated herbicide. This method allows the herbicide to be absorbed into the root system while the tree remains standing, which is sometimes preferred to reduce the risk of stream bank erosion near waterways.
Post-Treatment Management of Roots and Suckers
After the initial treatment, managing the willow’s aggressive root system and inevitable suckers is the final stage of permanent kill. Willows are notorious for producing new shoots, or suckers, from the roots or the base of the trunk as an attempt to survive the trauma. These suckers must be addressed immediately upon appearance, as they indicate the root system is still alive and trying to draw energy.
Treat any new suckers by cutting them off and applying a concentrated dose of the systemic herbicide to the fresh cut surface. This spot application allows the chemical to translocate directly into the remaining root network, depleting its energy reserves. Regular monitoring and repeated treatment of these suckers are required for several months, or even years, until no further growth appears.
Once the main tree is dead and the suckers are controlled, the stump can be left to decompose naturally, which takes many years, or mechanically removed with a stump grinder. Grinding the stump is a faster option, but the willow’s root system extends far beyond the stump’s diameter. The aggressive, shallow roots will eventually decay over a period of three to seven years once the tree is fully killed.