Sumac trees, such as the common smooth sumac or staghorn sumac, are often admired for their vibrant fall foliage but are widely considered a nuisance due to their aggressive growth habit. They are frequently confused with Poison Sumac, a distinctly different species that causes skin irritation. The primary challenge in removing these trees is their ability to form dense colonies, which requires a targeted strategy for permanent eradication. Understanding the plant’s biology is necessary to apply effective removal methods.
Why Sumac is Difficult to Eradicate
The persistence of sumac stems from its specialized root system, which is designed for rapid colonization and regeneration. Unlike single-trunk trees, sumac develops an extensive network of shallow, lateral roots called rhizomes that spread far from the original plant. These rhizomes contain numerous dormant buds capable of producing new shoots.
When the main stem is cut down or damaged without treating the root system, the plant responds by activating these dormant buds. This process, known as suckering, causes a massive flush of new shoots to sprout up from the rhizomes across a wide area. Simply cutting the tree down encourages the creation of an even denser colony, making sustained treatment a necessity.
Non-Chemical Removal Techniques
For those preferring to avoid herbicides, sumac can be removed through labor-intensive mechanical and cultural controls, though success requires patience. One method involves the complete manual excavation of the entire root crown and all lateral rhizomes. This is physically demanding work because the shallow roots can extend many feet, and any small segment left behind can still generate a new plant.
A less aggressive approach involves persistent, repeated mowing or cutting of all visible shoots. This must be done consistently throughout the growing season for several years to slowly deplete the carbohydrate reserves stored in the root system. The goal is to starve the plant by preventing photosynthesis, eventually killing the entire underground network.
Smothering is another non-chemical option that works by blocking sunlight from reaching the leaves and new shoots. This method involves covering the entire affected area with a thick, opaque tarp or heavy plastic sheeting. The cover must remain in place for at least one to two full growing seasons to fully solarize the area and kill the root system beneath.
Effective Herbicide Application Methods
Chemical control is the most reliable and fastest method for achieving permanent sumac eradication, but it must be applied specifically to overcome the plant’s defenses. Foliar spraying is often ineffective because sumac leaves have a waxy coating that resists absorption, and the chemical rarely translocates in high enough concentration to kill the root system. Targeted application methods ensure the herbicide moves directly into the plant’s circulatory system and down to the roots.
Cut-Stump Treatment
The most effective strategy is the Cut-Stump Treatment, which involves cutting the main stem close to the ground and immediately applying a concentrated herbicide to the fresh cut. The herbicide, typically containing glyphosate or triclopyr, must be applied to the cambium layer—the thin, wet ring just inside the bark—within minutes of cutting. This narrow band is where the plant’s nutrient transport takes place, allowing the chemical to be pulled down to the rhizomes before the wound seals itself.
Basal Bark Treatment
For larger colonies with multiple small stems, or for individual stems less than six inches in diameter, the Basal Bark Treatment is an alternative. This method uses an oil-soluble triclopyr formulation mixed with a basal oil. The mixture is sprayed in a band around the entire circumference of the lower 12 to 18 inches of the trunk, penetrating the bark and carrying the chemical into the plant’s vascular system to kill the roots.
It is necessary to follow all manufacturer instructions for concentration, mixing, and application timing, as using too weak a mixture or applying it improperly will encourage more suckering. When handling concentrated chemicals like triclopyr or glyphosate, appropriate personal protective equipment (PPE), including gloves and eye protection, must be worn. Treating any new suckers that emerge in subsequent seasons with a direct cut-and-treat application is often necessary to achieve complete control.