En EspaŅol

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.

Help us grow by giving to the Plant Database Fund or by becoming a member

Did you know you can access the Native Plant Information Network with your web-enabled smartphone?

Share

Ask Mr. Smarty Plants

Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

Search Smarty Plants
    
 
See a list of all Smarty Plants questions
Can't find the answer in our existing FAQs, submit a question to Mr. Smarty Plants.
Need help with plant identification, visit the plant identification page.
 
rate this answer
Not Yet Rated

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. Jo

ANSWER:

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

Eliminating smartweed from pasture in Oswego NY
August 28, 2009 - How do I get rid of smartweed in my pasture?
view the full question and answer

Invasive common giant mustard
March 14, 2007 - I have been seeing a lot of a small shrubby plants with yellow flowers all over Austin, mainly along roadsides. Back in my day the first wildflowers of Spring were the paintbrushes and the bluebonnets...
view the full question and answer

Smarty Plants Exotic Species
March 26, 2004 - What is an Exotic Species?
view the full question and answer

Avoiding planting Indian Paintbrush in Hawaii because of invasiveness
March 01, 2007 - My daughter is living in Hilo, Hawaii. For her birthday, her boyfriend ordered her some Indian Paintbrush seeds. Trying to be sure she grows them correctly in a pot, she found instructions that say ...
view the full question and answer

Eliminating suckers from roots of Moraine locust in Hilliard, OH
July 07, 2009 - We removed a large Moraine Locust tree and also the stump. Now little trees from the roots are coming up. How do we get rid of these so something else can be planted?
view the full question and answer

Smarty Plants's Facebook profile Support the Wildflower Center by Donating Online or Becoming a Member today.

Mr. Smarty Plants wants you to be his Facebook friend. Click the Facebook icon to add yourself to Mr. Smarty Plants list of friends.
E-NEWSLETTER | BECOME A MEMBER | DONATE NOW | MEDIA | SITEMAP
© 2014 Lady Bird Johnson Wildflower Center