Sumac varieties, such as Staghorn (Rhus typhina) and Smooth Sumac (Rhus glabra), are aggressive, fast-growing shrubs that quickly form dense colonies. They spread primarily through extensive, shallow underground root systems, which constantly generate new shoots called root suckers. Cutting the main trunk is not an effective control method because it triggers a defensive response, causing the plant to rapidly send up dozens of new suckers. Permanent eradication requires a targeted approach that moves systemic toxins into the entire root network. Before beginning removal, correctly identify the plant, distinguishing non-poisonous sumac from the toxic Poison Sumac (Toxicodendron vernix).
Identifying Your Target and Preparing the Stump
The first step is confirming the target is a common sumac and not the toxic Poison Sumac, which causes a severe skin rash. Common sumac species feature reddish fruit clusters that stand upright on the branches, and their compound leaves have serrated edges. In contrast, Poison Sumac grows in wet, swampy areas, produces drooping clusters of white fruit, and has compound leaves with smooth edges.
Once identification is confirmed, cut the main trunk as close to the ground as possible, leaving a stump two to four inches high. This low cut minimizes visible biomass and concentrates the target area for chemical application. The timing is crucial because the cut surface will quickly begin to seal over, preventing the uptake of herbicides. The chemical treatment must be applied to the freshly cut stump surface within minutes of the cut being made to ensure the plant absorbs the poison before the wound seals.
Targeted Chemical Eradication Methods
Chemical control is the most reliable method for killing the entire sumac root system and preventing the vigorous suckering response. The most effective products are systemic herbicides specifically formulated for woody plants, primarily those containing high concentrations of Triclopyr or Glyphosate. Triclopyr is considered more consistently effective on woody species than Glyphosate, even when applied at any time of the year. These systemic poisons travel through the plant’s vascular system down into the roots, which is necessary for complete eradication.
Cut-Stump Treatment
The most successful method is the Cut-Stump Treatment, which involves applying a concentrated herbicide mixture directly to the freshly cut surface. For larger stumps, the treatment must focus specifically on the cambium layer—the thin, moist ring located just inside the bark—as this is the active tissue responsible for transporting the herbicide to the roots. A solution of 50% concentration or greater is required for this method. Triclopyr ester products are often mixed with an oil-based carrier to improve bark penetration. On stumps larger than six inches in diameter, drilling downward-sloping holes into the stump surface before applying the chemical can improve absorption deep into the xylem tissue.
Basal Bark Treatment
For smaller saplings or new suckers where cutting is impractical, the Basal Bark Treatment is an effective alternative. This method uses an oil-soluble formulation of Triclopyr, such as Triclopyr ester, mixed with a basal oil to penetrate the bark. The mixture is applied to the entire circumference of the lower 12 to 18 inches of the trunk, including the root collar area. The bark must be thoroughly wet but not running off the stem. Foliar spraying of the leaves is not recommended for established sumac because it kills only the above-ground growth, stimulating a massive flush of new root suckers.
Strategies for Herbicide-Free Removal
For readers seeking to avoid chemical treatments, several alternative, labor-intensive strategies can eventually deplete the sumac’s root reserves.
Girdling
Girdling, or ring barking, involves removing a continuous strip of bark and the underlying cambium layer completely around the trunk. This action starves the root system by stopping the downward flow of sugars produced by the leaves. This is a slow process that can still prompt the plant to send up new suckers initially.
Solarization
Solarization involves smothering the area to deny the roots light and heat them to lethal temperatures. After cutting the main stems to ground level, a heavy, clear plastic sheet or tarp is secured tightly over the entire affected area. It should be left in place throughout the hottest months of the year. The clear plastic traps solar heat, raising the soil temperature to between 104°F and 131°F (40°C to 55°C) in the upper soil layers. This can kill shallow roots and dormant buds over a period of four to six weeks.
Physical Removal
The most physically demanding method is Relentless Physical Removal, which relies on exhausting the plant’s stored energy. This involves continually cutting, mowing, or tilling any new shoots as soon as they appear above ground, ideally repeating the process twice during the summer growing season. Because the sumac root system is shallow, repeated removal of the new shoots prevents photosynthesis and starves the underground root network over one to two full growing seasons.
Managing Persistent Root Suckers
Even after the main trunk has been treated, the sumac’s extensive root system can remain viable for many months. Vigilance is mandatory, as the root system may take up to a year or more to die completely, making follow-up treatment of new growth essential for full eradication. These new shoots, or root suckers, represent the plant’s attempt to survive by reactivating dormant buds along the rhizomes.
When new suckers appear, they must be addressed quickly before their leaves can begin photosynthesizing and recharging the root system’s energy reserves. The most effective approach is a targeted spot-treatment using a concentrated herbicide.
Spot Treatment Methods
- Cut the new sucker close to the ground and immediately apply a high-concentration product to the small cut surface, similar to the cut-stump method.
- Apply a low-concentration foliar spray, such as a 2-3% aqueous solution of a Glyphosate or Triclopyr product, to the leaves of the new sucker, ensuring minimal drift onto desirable plants.