Native Plants
![](../_images/smarty_plants.gif)
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.
![](../_images/mr_smarty_plants_logo_web_200w.jpg)
rate this answer
![](../_images/star_00.gif)
Monday - September 01, 2014
From: Pleasant Valley, NY
Region: Northeast
Topic: Non-Natives, Problem Plants
Title: Aggressive Plants in Pleasant Valley NY
Answered by: Larry Larson
QUESTION:
Are there any native plants that can out compete Japanese knotweed?ANSWER:
Mr Smarty Plants has been chewing on this question a bit. We are all about the sustainable use and conservation of native wildflowers, plants and landscapes. Japanese Knotweed [Fallopia japonica] is an import from Eastern Asia and Japan and is renown for its aggressive nature. As such, it’s both non-native and an invasive species, so it’s not in our records.
My first reaction to your question is “unlikely to no”. These links from a search on “Japanese Knotweed” indicated that it is a highly successful invader that crowds out native plants and that it is extremely hard to eradicate.
Fallopia Japonica from Wikipedia
National Invasive Species Record
Eradication of Japanese Knotweed Plants
And here is the report from the New York Invasive Species Clearing House
The end result of this is that all the experts agree that this is one of the most aggressive invasive species that is present in the US!
I imagine that the question behind your question is that you have a small infestation of the stuff [I hope not!] and would like to control it. The process suggested above is to regularly cut it down so that it cannot active spread further, limiting its growth. It’s possible that some aggressive native plants, such as Campsis radicans (Trumpet creeper) might be competitive, but then you would have two really aggressive plants present and no relief indicated!
Still looking for a way to say “yes” to you: Based on the really general nature of your question, we can go a bit farther afield in theory and note that Fallopia Japonica also has a range of territory and climates where it is acclimated.
It is adapted to Coastal Asia and Japan. This USDA link illustrates that it invades a similar climate range in North America, and that it does not extend to Florida, the desert Southwest or to the frigid North. So – The native plants that CAN outcompete the Japanese Knotweed are the cacti of Southern Arizona/Nevada, pure Florida natives, or natives to the Yukon – when the invaders vitality is compared to them in their own ecoregion!
From the Image Gallery
More Non-Natives Questions
Use of non-native Indian Mustard for reducing lead in soil
February 07, 2007 - The EPA phytoremediation documents say lead contamination can be reduced with Brassica juncea:
"Successful Reduction of Lead Contamination.
Phytoextraction was demonstrated at a site in Tren...
view the full question and answer
Disappearing oranges from Satsuma orange in Austin
June 25, 2008 - I had many tiny future oranges on my Satsuma Orange Tree until a few days ago. Suddenly, all were gone except one. They weren't on the ground and the tree itself seems incredibly healthy. It is gr...
view the full question and answer
Pruning Citrus Suckers
October 06, 2014 - Mr. Smarty Plants, you are the only person that has "not" insisted that the little balls on Satsuma and lemon trees were clumps of bugs. They are surely what you described in the answer to my previo...
view the full question and answer
List of North American plants grown in other countries
August 17, 2008 - I am working on a childrens story and would like to let the teachers who read this book know where some of the native plants in my book grow throughout the world, or if they grow outside of the USA. p...
view the full question and answer
Plant identification
June 12, 2014 - We live in Magnolia TX and have a shrub we can't identify.
It's evergreen and
has waxy leaves with a serrated edge that are about an inch in length.
They have pink flowers and
they grow to ab...
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |