Tuesday, August 16, 2016

Invasive Species Spotlight: Devil’s Tail

Guest post by Jacqueline Hyman 

Devil’s Tail (Persicaria perfoliata), also known as Mile-A-Minute weed, is a fast-growing invasive that shrouds other plants, preventing them from receiving important nutrients and sunlight. 

    The plant was introduced to Beltsville, MD, in 1937, as well as in other parts of the United States, according to Plant Invaders of Mid-Atlantic Natural Areas. It was also introduced to a nursery site in York County, PA, in the 1930s, which is likely the source of the plant’s growth in the Mid-Atlantic and northeastern U.S., according to the book.

   University of Maryland Extension Educator Charles Schuster said the plant thrives in many conditions, including farmland, landscapes, and nurseries.

   “I find it everywhere I go,” said Schuster, who works in commercial horticulture. “There’s not an area that I have not found it in my normal travels.”

   Mile-A-Minute is an annual trailing vine, with pale green triangular leaves. It also has what Schuster calls a reverse-facing thorn.

  “Instead of having a thorn at a direct right angle to the stem facing toward the outside of the stem, this has a thorn that as you grab the stem and start to pull and your hand slides a little bit, it literally digs in,” Schuster said.

   This thorn is one way the plant spreads and repopulates, as it can dig into people and animals, being dragged through different areas. Additionally, birds eat the seeds and spread the plant that way, Schuster said.

   Water is also an “important mode of dispersal as fruits can remain buoyant for seven to nine days,” according to Plant Invaders.

   Schuster said the plant likes temperatures 70 degrees and above, and grows aggressively.

    “In optimum conditions with adequate soil moisture and appropriate temperature, Mile-A-Minute will take off, and it will grow inches in a day,” he said. "It is very aggressive in that you have a bare spot in a forest or a bare spot in a landscape …  this is the type of one that will aggressively take that spot, grow up into the shrubbery, up in the trees."

    Devil’s Tail is in competition with other plants for moisture, and during dry times sucks up a lot of moisture that other plants need, Schuster said. It also forms a canopy over other plants, preventing them from getting the necessary sunlight, diminishing ability for photosynthesis.

    Many herbicides, including natural ones, will kill Devil’s Tail, Schuster said.

   "It’s an easy-to-control weed from the aspect there’s a lot of chemicals that will knock this out quickly and easily," he added. However, Plant Invaders recommends biological control.

   Schuster said in his own garden, he simply puts on a pair of gloves and pulls the weed. Gloves are important when dealing with this plant in order to avoid injury, he said, because of its unique thorn.

    “If I’m not to the point of where it’s having berries, I’ll just pull and drop it and let it decay right there on sight,” said Schuster. “It might not be the most beautiful way of doing it, but I’m trying to recycle as much as I can right on the site on which it’s found.”

   In order to prevent spreading the plant, people should check to make sure they are not carrying it when visiting forested areas or anywhere the plant might thrive. "If you see it catch onto you, you should make sure you remove it so that you’re not taking it to a new location, especially home," said Schuster.

The  "Invasive Species Spotlight" is a summer blog series focusing on a different plant each week that is a problem for Mid-Atlantic home gardeners.

About the author:
Jacqueline Hyman is a junior journalism and English major at the University of Maryland. She is the editor-in-chief of the Mitzpeh, an independent Jewish newspaper at UMD. In addition, Jacqueline enjoys musical theater, and teaches piano and voice at Guitar Center. She is excited to be interning this summer for the Washington Gardener

Image credit:
At top, Persicaria perfoliata (non-native) by Leslie J. Mehrhoff, wikipedia commons.
At middle, Mile-a-minute thorns by Dalgial, wikipedia commons.
At bottom, Mile-a-minute in flower/fruit Washington Gardener Magazine.

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