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 - May 14, 2012

From: San Antonio, TX
Region: Southwest
Topic: Invasive Plants, Herbs/Forbs
Title: Invasive American Germander from San Antonio
Answered by: Barbara Medford

QUESTION:

I brought home some American Germander (Teucruim canadense) - page 259 In Wildflowers of Texas by Geyata Ajilvsgi - from a railroad right-of-way. Since it is a member of the mint family it has become super invasive in my wildflower garden. I have tried solarization, Roundup, tilling and mulching to kill it but none of these methods have been successful. Do you have any suggestions? Maybe Ornamec?

ANSWER:

We have probably mentioned this before, but the best way to control invasives is to never plant them. Because Teucrium canadense (Canada germander) is a member of the Lamiaceae (mint) family it is unusually invasive. You can see from this USDA Plant Profile map that it is indeed native to Bexar County and to a whole lot of the surrounding area.

We did some research on the herbicide Ornamec, and discovered that it is a grass killing herbicide. In other words, it will kill monocot plants, grasses, and not touch dicots, or broad-leaved plants. So you would add a toxic material to your garden soil that would not faze the germander at all. Always research the specific purposes of a herbicide before you purchase or apply it.

We learned that the Teucrium canadense spreads by underground rhizomes, so that even an appropriate herbicide would probably not be able to get to those rhizomes. We also learned that it appears to be a wetland plant. If you have wildflowers native to the Bexar county area, you could probably water them less and at least discourage the germander. However, you also need to get down and root out those rhizomes, getting the tubers that store food for the plant and ensure its safety from the herbicides. There is no quick solution to a plant that can protect itself this easily. Of course, you should always cut down the plant before it has a chance to bloom and seed, as that is another way it spreads.

If worse comes to worse, you can try the paintbrush and herbicide method. Get a small amount of undiluted herbicide, the kind for dicots or broad leaf plants and some small disposable sponge paintbrushes. Full disclosure: This is hands and knees work and not easy. One at a time, clip the stem of the germander as close to the earth as possible. Then, within 5 minutes, paint the cut edge with the herbicide. You need to do it quickly because the plant will try to heal the cut over to protect the very rhizomes you are trying to kill. And keep pulling them out, digging out the rhizomes.

Next time you see some wildflowers in a wild situation, step away from the plant.

 

From the Image Gallery


Canada germander
Teucrium canadense

Canada germander
Teucrium canadense

Canada germander
Teucrium canadense

More Herbs/Forbs Questions

Native plants for pots for wedding in November
October 03, 2006 - Will any of the plants that are in your big plant sale be flowering in November? I am looking for plants that would do well in pots because I'd like to use them as center pieces at a wedding (in Aus...
view the full question and answer

Butterfly garden from Buffalo, NY
February 20, 2014 - I'd like to replace the grass in my front yard with a native butterfly garden that will suit the larval and adult stages of butterflies in Western New York. The patch in question faces north and gets...
view the full question and answer

Chlorosis in tropical milkweed and asclepias tuberosa
May 18, 2008 - I planted both tropical milkweed and asclepias tuberosa. Both are chlorotic and the native milkweed has brown upturned leaves. Could it possibly be too much water? Or what?
view the full question and answer

Light requirements for Heartleaf Skullcap from Smithville TX
June 29, 2011 - How much sun or shade does Heartleaf Skullcap need?
view the full question and answer

Perennials for a Horse Pasture in Colorado
May 15, 2014 - I am looking for horse-resistant perennials for zone's 2-4. I live at 9,000 feet in Crested Butte, CO.
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