Eradicating Persistent Box Elder Suckers After Stump Removal

Four years after cutting down a mature box elder and grinding the stump a foot below ground, you’re still battling a relentless surge of root suckers. Despite repeated root grinding, brushing killer applications, and manual root removal, new shoots keep appearing—threatening your plans for a garden. The problem: brush killers only top-kill foliage; they don’t translocate to the root system.

Why Suckers Persist

Box elder (Acer negundo) is notorious for aggressive root sprouting. When the main trunk is removed, the extensive root system survives and sends up shoots (suckers) to photosynthesize and rebuild energy reserves. Mechanical removal or contact herbicides that don’t reach the roots simply stimulate more sprouting.

Effective Solution: Systemic Herbicide Application

Use a glyphosate-based herbicide (e.g., Roundup) applied directly to the sucker foliage. Glyphosate is translocated through the plant to the roots, killing the entire underground network.

Step-by-Step Method

1. Timing: Apply when suckers are actively growing (late spring to early fall) and leaves are fully expanded.
2. Concentration: Use the product straight from the container (ready-to-use) or mix at the highest label rate for tough woody plants.
3. Application: Wear chemical-resistant gloves. Wet a cloth or sponge with the herbicide and wipe it onto the leaves of each sucker, thoroughly coating the foliage. Alternatively, use a low-pressure sprayer, shielding nearby desirable plants with cardboard or plastic.
4. Persistence: Repeat every 2–3 weeks as new suckers emerge. The root system will gradually deplete and die.

Precautions

• Glyphosate is non-selective—avoid contact with grass, flowers, or shrubs you want to keep.
• Do not apply before rain; allow at least 6 hours of dry weather for absorption.
• Once suckers are controlled, wait several weeks before planting your garden to ensure no residual activity affects new plants (glyphosate binds tightly to soil and has no pre-emergent activity).

Alternative: Smothering

If you prefer a non-chemical route, cover the entire area with heavy black landscape fabric or 6+ inches of wood chips for a full growing season to starve the roots of light. This is slower but effective.

Final Thought

Box elder is tenacious, but consistent, targeted glyphosate applications will eventually exhaust the root system. Patience and persistence are key—your garden can happen!