Poisonous Pokeweed

In Southern Ontario where I write from this poisonous weed can be found growing in city neighbourhoods (as the photos below were), meadows and near the edges of woodland areas. It’s a good plant to learn how to identify since all parts of this plant are highly poisonous. Pokeweed (Phytolacca americana), is known by many names including dragonberries, and inkberry. It is a rather large perennial with a long and thick tap root, that can make this plant difficult to eradicate. In spite of the inherent risks it has traditionally been used for medicinal purposes, for red food coloring, as a wine coloring agent, and to make ink. According to WebMD a small child can be poisoned by consuming just 1 berry, where as 10 berries can be toxic to an adult. The plant is also poisonous to pets and livestock but not to birds, who enjoy feasting on the berries.

Identifying Pokeweed

Overall Growth Habit:

Pokeweed is a herbaceous plant but at maturity it tends to look more like a shrub or small tree. They typically grow to about 150cm-180cm (5-6′) tall although they can reach heights of 300cm (10′). The plant dies down to the ground each winter.

Young Pokeweed plants in early May.

Stems: are sturdy and erect, growing 120cm-300cm (4′-10′) tall and up to 10cm (4″) thick. They are usually hollow, smooth and hairless, and branched towards the top. Colour wise they are either reddish or green with red speckles.

The stems of Pokeweed have red speckles and the absence of an ocrea at the base of each leaf.
A new Pokeweed shoot arising from the base of last years plant. Notice the hollow stem.

Leaves: are lance-shaped, with prominent reddish veins and leaf stems (petioles). The undersides are either a lighter green or pinkish in colour. The leaves alternate up the stem singly, and become progressively smaller as they go up the plant. Leaves towards the base can be quite large, measuring up to 30-50cm (12-20″) long and 10-17cm (4-7″) wide. When crushed the leaves give off an unpleasant odour.

Young Pokeweed leaves in early May.

Flowers and Fruit: greenish-white flowers (racemes) appear at the ends of branches from June to October. These mature to juicy, purplish-red berries in late summer and fall.

Root: forms a thick, fleshy perennial taproot. This root is white in colour an can be over 30cm (1′) long and 10-15cm (4-6in) wide. The root is the most poisonous part of the plant.

Reproduction and Spread: pokeweed come back each year from their perennial tap root and spread by seed.

Control and Management of Pokeweed

Due to the poisonous nature of the plant you will need to where gloves before handling it, as the poison can be absorbed through the skin. Young seedlings should be hand pulled or mowed before they begin putting on a tap root. Once a tap root has formed you will need to either fully dig the root out or cut the plant well below the soil line repeatedly until you deplete the energy stored in the root, which could take years. Never let the plant flower, cut the flower heads off before they can produce seed. In some cases a systemic herbicide, such as glyphosate or 2, 4-D may be required. Repeat applications will likely be required for mature tap roots.

Symptoms of Pokeweed Poisoning

Pokeweed can cause “nausea, vomiting, cramping, stomach pain, diarrhea, low blood pressure, difficulty controlling urination (incontinence), thirst, and other serious side effects” (WebMD, (n.d.).

References:

Abbey T, (updated: Aug. 16, 2016). Common Pokeweed Identification and Management. Penn State Extension. https://extension.psu.edu/common-pokeweed-identification-and-management?msclkid=66f7fc5eceba11ec89a85502046c8498

Cornell University, (n.d.). Common Pokeweed. Cornell Weed identification. https://blogs.cornell.edu/weedid/common-pokeweed/?msclkid=a36b0c45cecd11ec80c69c6f53112782

OMAFRA, (updated: Feb. 12, 2021). Ontario Weeds: Pokeweed. Excerpt from Publication 505, Ontario Weeds. http://www.omafra.gov.on.ca/english/crops/facts/ontweeds/pokeweed.htm?msclkid=66f93b6eceba11ecb3d99939c453ba9f

WebMD, (n.d.). Pokeweed – Uses, Side Effects, and More. https://www.webmd.com/vitamins/ai/ingredientmono-220/pokeweed

Photo Credits: all photos taken by the author.

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