Japanese Knotweed

1
Japanese Knotweed
(Polygonum cuspidatum)

• Kaitlan Biondi, Sarah Bock, Morgan Stuart,
  Christina Zanic

2
Overview of Invasive Species

• What is an Invasive Species?
• gAny organism non-native to the ecosystem
• gAn organism in which its introduction to the
  ecosystem causes or is likely to cause
  environmental or economic harm
• gInvasive species can be plants, animals or
  microbes introduced into a foreign environment.

3
Examples of Invasive Species

• Plants
• gJapanese Knotweed
• gPhragmites
• gMarijuana

• Animals
• gNutria
• gCane Toad
• gSnakehead

4
What can invasive species do?

• Invasive species threaten native species
• Plants, animals, and parasites out-compete native
  crops for soil and water
• Organisms can destroy natural resources like
  forests
• Aquatic invasive species like the Zebra Mussel
  can clog waterways and affect things like
  irrigation and transportation
• Introduce new diseases that affect human health
• Cross-breeding between native and non-native
  species can alter the genetic makeup of native
  species

5
Description of Japanese Knotweed

• Upright, shrub-like herbaceous perennial
• Grows from three to ten feet in height
• Stout, round, hollow stems
• Forms in dense clumps
• Leaves are two to six in. long, two to five in.
  wide
• Shiny black-brown three-sided seeds
• Greenish-white flowers in the summer

6
Introduction Distribution

• Brought to the United States as an ornamental in
  the late 1800s

• Affects 36 states in the lower 48 from Maine to
  Wisconsin to Louisiana
• Also scattered in the Midwest and western states

7
Meadville, Pennsylvania
Japanese Knotweed can be found in numerous
locations near Allegheny College.

• Behind the Bio Building
• Along the Arterial Highway
• In the plaza near KFC
• Off of Liberty Street

8
Habitat

• Generally found in moist, open habitats
• Reported along riverbanks and islands, wetlands,
  along roadways, hillsides
• Can tolerate a variety of adverse conditions
  including full shade, high temperatures, high
  salinity, and drought

9
Threats

• Crowds out native plants
• Deep roots enable it to out-compete other plants
  for water and nutrients
• Reduces species diversity and damages wildlife
  habitat
• Very difficult to eradicate
• Can re-sprout from small fragments

10
Control

• Must be eradicated as early as possible upon its
  appearance
• Cut stalks as often as three times during the
  growing season
• Immediately follow with an application of
  glyphosate herbicide
• Several years of treatment may be needed

11
References

• www.invasivespeciesinfo.gov/plants/knotweed.shtml
• www.dcr.state.va.us/dnh/fspocu.pdf
• www.hort.uconn.edu/cipwg/art_pubs/TNC/html/nat_jap
  hnot.html
• www.dcnr.state.pa.us/forestry/invasivetutorial/jap
  anese_knotweed_M_C.htm
• www.nps.gov/plants/ALIEN/fact/pocu1.htm
• www.ecy.wa.gov/programs/wq/plants/weeds/aqua015.ht
  ml