Poisonous Pokeweed Out in Force Amid Central U.S. Weeds, Plantings

Manhattan, Kansas (September 9, 2010) -– Some examples of a dangerous weed with big shiny leaves and hanging clusters of purple-back berries are now tall enough to stand out in the company of central U.S. crops, weeds and garden plants. Thick and fleshy, its purple-red stems can mature at 3 to 8 and sometimes 10 feet tall.

“This summer, we’ve received a number of phone calls about the plant. Evidently, common pokeweed got off to an unusually good start in June. Nowadays, it’s sticking out all over the place like some kind of sore thumb. Where the plant is multi-stemmed, it may even look shrubby,” said Ward Upham, horticulturist with Kansas State University Research and Extension.

Pokeweed is unusual among weeds in that every one of its parts is poisonous, Upham warned. Plus, the plant becomes increasingly dangerous to humans, pets and livestock as it grows. No matter pokeweed’s age, however, the toxicity of its parts also ranges. The least hazardous is the plant’s children- and bird-attracting berries. The most is pokeweed’s large white tap root -- which can get as big as a bowling ball.

“Strangely, pokeweed has a long history of human use, particularly if you were a native Indian interested in a short-lived crimson dye or a violent cure for stomach cramps – which could include diarrhea, vomiting or both. From pioneer through medicine show days, people used pokeweed to treat everything from rheumatism to hemorrhoids,” he said. “Today, some of us still harvest its leafy shoots in spring, to cook and eat as greens.

“Even though the plants are then at the low point of their emerging toxicity, you’ve got to cook those shoots thoroughly -- at least twice, disposing of the water each time. Handling and preparing the shoots will be hazardous, too. You can absorb pokeweed juice through your skin.”

Fortunately, the plant tastes “pretty awful,” Upham said. Livestock will avoid it if other food is available.

Unfortunately, birds are fond of the berries. So, they often distribute each berry’s eight to 10 seeds with a bird-dropping fertilizer. Pokeweed is a tough perennial, and its tap root gets larger every year. One treatment with a strong herbicide (e.g., 2,4-D) may not kill anything other than top growth.

“If you just have a few of these weeds, I’d recommend digging them out, removing as much of the tap roots as you can. Then get rid of them. Don’t even put the plants in your compost pile,” Upham said. “If you can, also approach pokeweed as you do poison ivy. Or, at the very least, wear a tough long-sleeved shirt and gloves.”

Contact:
Ward Upham
wupham@ksu.edu