The mulberry tree (Morus) is often sought for removal due to its rapid growth and vigorous nature. This species is difficult to eradicate completely because of its aggressive root system, which sends up new shoots. The tree’s persistence is rooted in the energy reserves stored within its extensive network of roots, allowing it to regrow repeatedly even after the main trunk is cut down. Complete eradication requires a systemic approach to destroy the entire root structure, not just felling the tree.
Initial Physical Removal and Preparation
The first step is safely felling the tree and removing the main trunk. The remaining stump should be cut as close to the ground as possible to make subsequent treatments easier. If the stump is not treated, the massive root system will quickly begin to expend its stored energy by producing numerous new sprouts.
The success of any follow-up treatment hinges on accessing the tree’s vascular system immediately after the cut is made. The cambium, a thin layer of living tissue just beneath the bark, transports nutrients and is the target for chemical application. The herbicide must be applied quickly, ideally within minutes, to ensure maximum absorption before the cut surface dries out and seals off. For larger stumps, the cut surface should be made level to facilitate an even application.
Targeted Chemical Eradication Methods
Chemical application is generally the most reliable method for ensuring the death of the entire mulberry root system. Herbicides with active ingredients such as concentrated Glyphosate or Triclopyr are recommended. These chemicals are translocated downward through the phloem to the roots, causing a complete kill of the underground biomass.
The Cut-Stump Treatment involves applying concentrated herbicide directly to the freshly cut stump. Application should focus exclusively on the outer ring of sapwood and cambium, as the heartwood is dead and will not absorb the chemical. This targeted application minimizes chemical use while maximizing absorption into the active transport tissues.
For standing trees or larger stumps, the Frill/Hack-and-Squirt method provides an alternative path for the chemical. This involves using an axe or hatchet to make downward-angled cuts completely around the circumference of the trunk, penetrating the cambium layer. Herbicide is then squirted directly into each cut, allowing the chemical to enter the vascular system before the tree can seal the wound.
A third method, the Basal Bark Treatment, is best suited for smaller trees or root suckers with thin bark. An oil-soluble formulation of a chemical like Triclopyr is mixed with a penetrating oil and sprayed entirely around the circumference of the lower 12 to 18 inches of the trunk. The oil helps the herbicide penetrate the bark and move into the phloem, killing the tree without the need for cutting.
Non-Chemical Strategies for Systemic Killing
For those who prefer to avoid chemical herbicides, non-chemical methods can still achieve systemic root death, though they require more time and patience. The principle is to permanently disrupt the tree’s ability to produce and store energy in its root system. This prolonged starvation eventually leads to the death of the entire plant.
One method is Girdling, which involves removing a complete, continuous band of bark and the underlying cambium from around the trunk. A strip at least two to three inches wide must be removed to ensure the phloem layer, which transports sugars from the leaves to the roots, is completely severed. The tree can still transport water and nutrients upward in the xylem, but the roots will slowly starve over a period that can take a year or more.
Another option is Stump Smothering, which prevents any new photosynthetic growth from emerging. This method requires covering the entire remaining stump with a heavy, opaque material like thick plastic sheeting or a deep layer of organic mulch. Preventing light from reaching the stump surface stops sprouts from photosynthesizing, depleting the root system’s stored energy over time. While this is environmentally friendly, it is a slow process that demands consistent monitoring to ensure no suckers breach the covering.
Managing Aggressive Suckering and Root Regrowth
Even after successful treatment of the main stump, mulberry trees send up numerous root suckers, sometimes emerging many feet away from the original trunk. These sprouts arise from latent buds along the root system and quickly grow into new trees. Simply mowing or cutting these suckers at ground level is counterproductive, as the action stimulates the root system to produce more growth.
Effective long-term management requires either repeated physical removal or targeted chemical treatment of the suckers. If choosing a chemical approach, the basal bark treatment can be applied to the base of individual suckers less than four inches in diameter. Alternatively, a foliar spray of a broadleaf herbicide can be applied directly to the leaves when they are actively growing. The chemical is absorbed by the leaves and transported down to kill the root sections that produced the sprout. Consistent monitoring and immediate treatment of new growth are necessary to exhaust the widespread root system.