En EspaÑol

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?


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

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


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


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

Planting petunias around base of oak tree from Houma LA
March 30, 2013 - I live in south Louisiana and I want to plant petunias. Can I plant petunias around the base of an oak tree?
view the full question and answer

Is Canna glauca invasive?
June 10, 2015 - How aggressive is Canna glauca? I'm interested in planting one near a gutter downspout, but I'm afraid it will crowd out groundcovers (heartleaf skullcap and fall obedient plant) in the two location...
view the full question and answer

Can rose Zephirine Drouhin damage brick from Springfield IL
August 22, 2010 - Can ZÉPHIRINE DROUHIN damage brick?
view the full question and answer

Can a mustang grape and an oak coexist in Austin
November 04, 2009 - I have a healthy mustang grape vine growing on an oak in my yard. While the vine provides plenty of good food and a pleasant environment for many birds throughout the year, I feel it is overtaking the...
view the full question and answer

How to get rid of Japanese knotweed (Polygonum cuspidatum)
July 28, 2008 - 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 so...
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.
© 2015 Lady Bird Johnson Wildflower Center