Native Plants
Q. Who is Mr. Smarty Plants?
A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.
Did you know you can access the Native Plant Information Network with your web-enabled smartphone?
Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.
rate this answer
Monday - July 28, 2008
From: Washington, CT
Region: Northeast
Topic: Invasive Plants, Problem Plants
Title: How to get rid of Japanese knotweed (Polygonum cuspidatum)
Answered by: Nan Hampton
QUESTION:
We have an enormous stand of japanese polygonum that we are trying to get rid of. What soil type is the most inhospitable to this aggressive and highly invasive species? Were thinking of planting some native white pines in the area to grow over them as well as manually digging them out. What would you suggest? Thanks.ANSWER:
Polygonum cuspidatum (Japanese knotweed) is on the Least Wanted list of the Plant Conservation Alliance's Alien Plant Working Group. It appears from their description that nothing is inhospitable to this plant. As their web site states: "Japanese knotweed can tolerate a variety of adverse conditions including full shade, high temperatures, high salinity, and drought." Planting Pinus strobus (eastern white pine) over the area where the Japanese knotweed grows is a very nice idea, but it won't affect the status of the knotweed. Digging them out is the most environmentally friendly way to get rid of them; and, depending on the size of your population, it might be the best way to eliminate your plants. The Plant Conservation Alliance also gives specific instructions on chemical treatment for large or difficult populations. The Nature Conservancy and Clark County, Washington also have information on control programs and their success.
More Invasive Plants Questions
Skunk cabbage from Amsterdam NY
May 02, 2012 - Will skunk cabbage grow under a mobile home and cause odor?
view the full question and answer
Non-native invasive carrot wood tree losing leaves in Alpine CA
April 22, 2014 - My carrot wood tree is losing all of its leaves. The tree is about 15foot high & 13 years old. Could it be gophers? The tree was trimmed 1 year ago.
view the full question and answer
What is meant when Mimosa Tree is described as an invasive tree in San Antonio TX?
May 14, 2013 - When it is stated that the Mimosa Tree is invasive, does that mean that the Roots are invasive or does it mean that the seed pods will drop and make many more trees ?
view the full question and answer
Deer resistant plants from New Braunfels TX
August 31, 2012 - I have a 1/2 yard covered by a tree, shady. Bermuda grass previous owner planted has all turned brown this summer. I don't have lots of money to work with but would love to landscape that side of fr...
view the full question and answer
Are non-native Chinese pistache poisonous to alpacas from Galt CA
October 07, 2012 - Are Chinese Pistachio trees poisonous to alpacas?
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |