Poison Ivy

With extra moisture seen by much of the metro recently, you may be discovering a more offensive garden foe in your landscapes while weeding. Aggressive, pernicious, and toxic, poison ivy thrives in moist soil and can tolerate numerous types of both soil and lighting for germination. With summer also being the time of year that the plant flowers and berries, this leaves ample opportunity for seeds to be sown as wildlife consume and drop them in their travels. So, what can be done about these germinating adversaries?

It is first important to understand that poison ivy effects everyone differently. While some may have a very minor reaction to exposure, others may have severe reactions requiring medical attention. Therefore, when it comes to controlling poison ivy, the efforts should be done by someone that has a tolerance to them, with personal protective equipment like pants, long-sleeved shirts, and gloves utilized. If this means outsourcing control of the plant to someone other than yourself, than this is the action that should be taken as the control measure for the plant involve close interaction.

Poison ivy, in full grown form, is a vining plant that attaches to trees and shrubs via aerial roots. Every part of the plant, including leaves, stems, berries, and flowers, is considered hazardous, as they all contain the oil that ultimately becomes an irritant for humans. As with many other aggressive vines, the best form of eradicating poison ivy is repeated depletion of the carbohydrate storage in its roots, as this storage is what is used by the plant to continually re-sprout even after surface growth has been removed.

This in mind, addressing surface growth is the first task in removal, and there are a few different methods. Large vines should be cut at their base and carefully disposed of. They should not be burned, as the oils can travel in the air with smoke, creating a lung irritant. The base of the severed stems should then be treated with a broadleaf herbicide to hinder regrowth from the roots. Smaller just-sprouting plants can then alternatively just be hand pulled. For medium-size plants, a mower or trimmer may be carefully utilized to knock the plants back. Though varying, each of these approaches ultimately contribute toward the depletion of a viable root system for the plant.

Think you have poison ivy, but not quite sure how to identify it? The telltale signs of the plant are compound leaves of three (although this can be more), red stems, and rounded or toothed lobed margins (aka. indented leaf edges). If allowed to persist to autumn, the plant will also expose itself via bright red or orange fall foliage color. Also of note, while typically a vine, the plant can likewise appear in the form of a dwarf shrub.

In any instance of the plant, it is best to remember, foliage is required to keep it photosynthesizing, feeding itself, and contributing to its root storage. Control this foliage and you control the plant.

Anthony Reardon, Horticulture and Small Farms Agent, 2024

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