En EspaŅol
Share

Ask Mr. Smarty Plants

Mr. Smarty Plants - Controlling Pickerel weed (Pontederia cordata) in British Columbia

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

Tuesday - March 10, 2009

From: Burnaby, BC
Region: Canada
Topic: Invasive Plants
Title: Controlling Pickerel weed (Pontederia cordata) in British Columbia
Answered by: Nan Hampton

QUESTION:

Hello, I am emailing from the west coast of Canada, Vancouver, and I have a plant question regarding a species you have listed on your website. We have recently discovered Pontederia cordata L. Pickerel weed in a natural lake. On searching on-line, the plant is native to parts of the US but as a garden variety. Though it may not be officially invasive here, the garden variety has escaped into a natural area with fish and other wildlife value. As such, we would like to be proactive and control the species before it naturally spreads out of control. From your knowledge, what is the best way to control the species? Once the root system is established, I suppose we have to 'dig up' the roots to eradicate the plant? Any tips you can provide for this, so the work can be done with as little disturbance, would be greatly appreciated. As well, we are hoping to control spread of the plant by cutting off flowers before they seed. Any further suggestions or comments so we can control this plant is greatly appreciated! Kindly, Melinda Yong Environmental Technician

ANSWER:

Pontederia cordata (pickerelweed) is distributed over the eastern half of North America, including Quebec and Ontario.  There is also a population in Oregon.  The population in Oregon may be of a garden variety, but the ones in the eastern half of North America are wild native populations.  Nevertheless, P. cordata is included in the Southern Weed Science Society's Weeds of the United States and Canada list as an invasive and/or noxious weed.  I certainly understand your concern to find it in your lake—even though it is native to North America, it is not native to British Columbia.  Removing the flowers before seed set is certainly an important measure to use.  One recommendation for controlling emersed rooted aquatic weeds (such as P. cordata) given in Aquatic Weed Management: Control Methods by J. L. Shelton and T. R. Murphy from the the Southern Regional Aquaculture Center is to deepen the edges of the pond or lake since these emersed plants generally grow in shallow water (<2 feet).  This might or might not be practical depending on the size of your lake, but certainly you are going to have to use some mechanical or chemical means to remove or kill the plants and their roots.  According to Aquaplant (Texas Agrilife Extension Service, Dept. of Wildlife and Fisheries Sciences, Texas A&M University) mechanical or chemical control are the only control methods since there is no known biological control for pickerelweed.  You can read about various mechanical and physical control methods, as well as chemical controls, from the US Army's Aquatic Plant Information System Online.  The mechanical method with least disturbance to the lake is, of course, hand cutting and digging to remove roots and rhizomes.  Monitoring and diligence will be required afterwards to keep the plant under control.

Pontederia cordata

Pontederia cordata

Pontederia cordata

 

 

More Invasive Plants Questions

Getting rid of invasive grasses in backyard
July 17, 2010 - Mr. Smarty Plants, How do I rid my yard of invasive grasses? I am finding Bermuda, stickers, crabgrass and maybe even Johnson grass throughout my backyard. The invasion is substantial in one 200+...
view the full question and answer

Invasiveness of Cosmos from Decatur GA
April 26, 2013 - I have been searching for an answer concerning the invasive plant Cosmos. I know that Florida declares this but I have not been able to find out does Georgia? And specifically,is it only the yellow Co...
view the full question and answer

Landscaping a new yard in El Paso, TX
July 01, 2010 - I am starting my back yard, we want to plant some sod grass and shade trees. We were doing some research and came across the Paulownia and the Royal Empress tree. I like them since they grow very fast...
view the full question and answer

Identification of vine from Las Vegas NV
July 11, 2012 - I'm interested in identifying the vine shown by the leaf in this photo: https://picasaweb.google.com/lh/photo/zR3R4JSPYcCI4ESczNXWM4h8z33Cq5cyZNqSSYf9hx0?feat=directlink My mother-in-law got one o...
view the full question and answer

Invasive definition kalanchoe pinnata
June 05, 2006 - The plant Kalanchoe pinnata is listed as being invasive. What does that mean? Is it a weed or does it interefere with metropolitan plumbing? (root system)
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