Poison ivy is a common plant that causes an allergic reaction in most people. This reaction is due to urushiol, an oily resin found throughout the plant, including its leaves, stems, and underground root system. The roots are central to the plant’s survival and spread, making complete eradication challenging.
Identifying Poison Ivy Roots
Poison ivy roots exhibit distinct characteristics that aid in their identification. The plant develops a fibrous root system, including both underground runners (rhizomes) and taproots. These roots can spread horizontally, often forming new shoots where they contact the soil.
When poison ivy grows as a climbing vine, it produces “hairy” aerial roots along its stems, which help it cling to surfaces like trees, fences, or walls. The underground roots are typically shallow, usually staying within 12 inches of the surface, but they can spread extensively, sometimes up to 20 feet horizontally. These roots can appear bare or hairy, and contain the allergenic urushiol oil even in winter.
The Role of Roots in Poison Ivy’s Persistence and Spread
The root system is central to poison ivy’s resilience and invasive nature. These underground structures function as energy storage organs, allowing the plant to survive harsh conditions, such as droughts or the removal of its above-ground foliage. Even if the visible parts of the plant are cut back, the stored energy in the roots enables new shoots to emerge, leading to regrowth. Poison ivy propagates effectively through its roots and underground stems. New plants can sprout from these rhizomes, forming dense patches. This vegetative propagation, combined with seed dispersal by birds, contributes to its rapid spread. The extensive lateral spread of the roots means that removing only the visible plant can leave a vast network of underground roots ready to re-sprout.
Effective Root-Targeted Removal Strategies
Eradicating poison ivy requires targeting its root system.
Mechanical Removal
Mechanical removal, such as digging or pulling, can be effective for smaller plants or patches. When pulling, grip the plant as close to the root as possible to ensure the entire plant is removed. For more extensive patches, use a shovel to dig up the plants and their entire root system. Incomplete root removal often leads to regrowth.
Chemical Removal
Chemical methods using herbicides are often the most effective way to eliminate poison ivy, especially for larger infestations. Herbicides containing active ingredients like glyphosate, triclopyr, or a combination of dicamba, mecoprop, and 2,4-D amine are recommended because they are systemic. This means the chemicals are absorbed by the leaves and translocated throughout the plant, including the roots, to kill the entire system.
For optimal results, apply foliar spray herbicides when the poison ivy leaves are fully expanded and the plant is actively growing, typically on a sunny, calm day with temperatures between 60°F and 85°F and no rain in the forecast. If the poison ivy is growing among desirable plants, cutting the vine 2 to 3 feet above the ground and painting or spraying the cut end with a concentrated herbicide can effectively target the roots without harming surrounding vegetation. Multiple applications may be necessary to fully eradicate the plant.
Safety Precautions During Root Removal
When handling poison ivy roots, wearing appropriate protective gear is important, as they contain urushiol, the allergenic oil, even when the plant is dead. Direct contact with the roots can cause an allergic reaction.
Protective Gear
This includes long pants tucked into boots or thick socks, close-toed shoes, long sleeves, and water-impermeable gloves, such as vinyl or cotton. Thin rubber (latex) gloves offer limited protection as urushiol can penetrate them.
Disposal and Cleanup
Properly dispose of removed plant material to prevent further exposure. Place all poison ivy debris, including roots, in heavy-duty plastic bags, ensuring they are securely tied. Do not burn poison ivy, as the urushiol can become airborne in the smoke, causing severe respiratory irritation if inhaled. Avoid adding poison ivy to compost piles, as the urushiol can persist and cause reactions later.
After working with poison ivy, thoroughly clean all tools and clothing that may have come into contact with the plant. Urushiol can remain active on surfaces for many months or even years. Wash tools with rubbing alcohol or a degreasing soap and plenty of water. Launder exposed clothing separately in hot water with detergent. Immediately wash any exposed skin with rubbing alcohol, dish soap, or a specialized poison ivy cleanser, rinsing frequently with cool water to prevent the oil from spreading. Remember to scrub under fingernails where the oil can collect.