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_43.gif)
Monday - July 28, 2008
From: Chicago, IL
Region: Midwest
Topic: Invasive Plants
Title: Getting rid of Polygonum punctatum (dotted smartweed)
Answered by: Nan Hampton
QUESTION:
Dear Mr. Smarty Plants, After much online research, my property has been invaded by what I believe to be Persicaria polygonum punctata, more commonly known as dotted smartweed. I have tried horticultural vinegar but it only curled the leaves. Additionally, I have read that horticultural vinegar detrimentally changes the soil. These plants become at least three feet tall so it's hard to spray all parts of it. I have thought of covering them with clear plastic sheeting but don't know if that is enough heat to kill the roots. I feel my last resort is glyphosate, of which I have heard pros and cons. Digging them out is as horrendous as trying to comb out knotted hair and I do not have the time nor energy as they are everywhere. As I have said, I have been all over the Web looking for an answer as to how to kill these plants. Do you have any suggestions? I would really appreciate any advice you can provide. JoANSWER:
I assume you mean Polygonum punctatum var. punctatum (syn.=Persicaria punctata)(dotted smartweed), a plant native to North America. Another common name is water smartweed. Or, are you talking about Polygonum persicaria (spotted ladysthumb). This is an introduced species. Whichever one it is, the treatment will be the same. The most environmental friendly way, of course, would be to dig them out or pull them up. Alternatively, instead of spraying them you can cut them off near the ground and carefully paint or inject the cut stalk with herbicide. This would put the herbicide where it would do the most good and would be the least harmful to other plants and to the environment. If you spray them, you run the risk of harming other plants nearby that you want to save. Consult with the Cook County Extension Service or visit a reputable garden nursery for advice on the best herbicide to use. Please read carefully all instructions that come with the chemical and follow the safety guidelines to protect yourself and the environment.More Invasive Plants Questions
Bald cypress causing problems in Spring TX
June 22, 2010 - There is a 50+ ft Bald Cypress growing near my property line. While the tree has grown substantial knees along the driveway and some as far as 35 ft from the tree in my flower beds, I do not see any d...
view the full question and answer
Non-branching mimosa tree
June 26, 2008 - I have a Mimosa Tree, just about 2 years old, grown from seed. The problem with it is that it has not branched out, it looks like one long branch growing out of the ground, about 5 feet if stood strai...
view the full question and answer
Trees to replace some non-native invasives in Deltona FL
February 02, 2012 - I would like to replace 3 large ChinaBerry & 3 large Chinese Tallow trees in my good sized back yard with some local wildlife friendly trees native to the Deltona area(first area.) What do you recomme...
view the full question and answer
Comments on previous answer on non-native invasives from Raleigh NC
March 27, 2014 - https://www.wildflower.org/expert/show.php?id=7827
This answer is incorrect. Please have someone review it to remove the two invasive species you are encouraging people to plant by calling them nati...
view the full question and answer
Invasive plant in pond in Kenai, AK
May 02, 2009 - We built a pond in our back yard with materials from the beach. Including some plants. Didn't investigate the plants(our mistake). Well now it has taken over all of our landscape. It looks like ext...
view the full question and answer
Support the Wildflower Center by Donating Online or Becoming a Member today. |