Pokeweed (Phytolacca americana) is a robust, herbaceous perennial plant native to North America, recognized by its large size, purple stems, and dark berries. It is a frequent sight in disturbed areas, forest edges, and fence rows, often growing between four and ten feet tall. Pokeweed contains compounds toxic to humans and most livestock, leading to concern about its presence. The core question for many landowners is how this poisonous plant interacts with local wildlife, particularly white-tailed deer. Deer not only browse on pokeweed but often seek it out as a valuable source of nutrition.
Deer Interaction with Pokeweed
White-tailed deer frequently select pokeweed as a preferred late-summer forage. Wildlife biologists observe that deer show a high tolerance, or even immunity, to the compounds that sicken other animals. This makes pokeweed a valuable food source, especially during the summer when high-quality browse may become scarce.
The foliage of pokeweed is particularly attractive to deer due to its nutritional profile. The leaves can contain up to 32% crude protein, offering a dense nutrient package. Deer are concentrate selectors, meaning they actively seek out plants that offer high concentrations of nutrients or minerals, which pokeweed provides. The dark, purple-black berries that appear in late summer are also consumed, providing a valuable source of carbohydrates.
Deer browsing pressure on pokeweed can be intense, often showing heavy consumption of the leaves and stems. This high rate of consumption indicates that the plant is a desired component of the deer’s summer diet, not merely a last resort food. The ability of deer to safely consume this plant is likely due to physiological adaptations, possibly involving specialized bacteria in their rumen that neutralize toxic compounds.
Understanding Pokeweed Toxicity
Pokeweed’s toxicity stems from its concentration of saponins and oxalates, including the primary toxic compounds phytolaccatoxin and phytolaccigenin. All parts of the plant contain these substances, which cause severe gastrointestinal irritation and distress in humans and susceptible livestock. Toxicity levels are not uniform across the plant, varying significantly by part and maturity.
The highest concentration of toxins is found in the large, fleshy taproot, which should never be consumed. The mature leaves and stems contain the next highest levels of phytolaccatoxin. As the plant matures throughout the season, the concentration of toxins in the foliage and stems increases.
The berries are toxic to humans, especially when green. They contain a lower concentration of toxins than the root or mature leaves. Ingestion can still cause severe symptoms like nausea, vomiting, and abdominal pain. Though deer are largely unaffected, this toxicity profile is why the plant is largely avoided by cattle and other domestic animals.
Managing Pokeweed Presence
Controlling the presence of pokeweed requires persistence due to the plant’s robust perennial nature and deep taproot. For individual or small plants, manual removal is the most direct method. It is essential to dig out the entire taproot, which can be over a foot long, to prevent the plant from re-sprouting.
When handling the plant, wear gloves, as the sap can cause skin irritation in some individuals. For larger infestations, chemical control methods become necessary. Herbicides containing active ingredients like glyphosate or triclopyr are effective when applied to the foliage of actively growing plants.
Herbicide application is most successful when the plant is fully leafed out, ensuring maximum absorption. Preventing the spread of new plants relies on removing the berries before they ripen and drop their seeds. Since birds readily eat the berries and disperse the seeds widely, removing the clusters before they turn dark purple helps limit future infestations.