Knowledgebase

Wish I'd never heard of Poa Trivialis #874660

Asked June 25, 2024, 3:28 PM EDT

First, let me thank you for this service as I greatly appreciate any help you can provide to me. I had a new lawn sodded with blue grass last fall everything was beautiful until a few weeks ago when I noticed these yellowish spots in my yard. I am located in Austin, MN, but the lawn I am referring to is just south of Hayward, Wisconsin. Upon doing some research it appears to be poa trivialis. I would like to treat the weeds so my lawn can return to its original beautiful state. I am having trouble finding a solution. Any help you can provide is appreciated. Thank you again for this service!

Mower County Minnesota

Expert Response

I wish I had a good answer for you. Pop Trivialis is difficult to get rid of. 

How extensive it is will probably determine your course of action. You can try to pull it if it is not too extensive. It is intolerant of dry soil so it may be easier to get at this summer if we reach a dry spell. 

Do not over irrigate your lawn. 

If you choose to use an herbicide you will have to reseed the areas because it will kill all the grass in the treated area. 

Are you certain of your identification? One of your photos shows seed heads which is more likely to be poa annua. If this is the case you can use a pre-emergent next year. 

https://plants.ces.ncsu.edu/plants/poa-annua/

https://apps.extension.umn.edu/garden/diagnose/weed/grass/roughbluegrass.html

https://extension.psu.edu/lawn-and-turfgrass-weeds-roughstalk-bluegrass-poa-trivialis-l

https://turf.purdue.edu/poa-annua-poa-trivialis-in-lawns-and-athletic-fields/

Deb Reierson Replied June 27, 2024, 11:59 AM EDT
Do you feel that Acclaim Extra Selective Herbicide is a good choice to treat it?  



On Thu, Jun 27, 2024 at 10:59 AM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied June 27, 2024, 11:41 PM EDT

It does not say anywhere on the label that this herbicide is effective on Poa Trivialis.  It does say that it is not effective on sedges. 

We don;t recommend using any herbicide unless the label specifically states that it will be effective on the plant you want to get rid of. 

This is highly toxic to fish and aquatic systems so if you are near a water system I wouldn’t’t use it either. 

If you do try it, be sure to follow all label instructions, buy only what you need now, and wear protective clothing.

https://transportation.ky.gov/Maintenance/Pesticides/Acclaim%20Extra.pdf

Deb Reierson Replied June 29, 2024, 8:25 AM EDT
One follow up question if I may. My Poa showed up in my sod that was put down last August. Was the Poa in the sod? What it in the topsoil? How did this infestation suddenly appear this summer ?

Thank you in advance ! 

Pat

On Sat, Jun 29, 2024 at 7:25 AM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied July 03, 2024, 11:10 PM EDT

It’t impossible to tell if it was in the sod or the soil. 

Sorry.


Deb Reierson Replied July 05, 2024, 4:15 PM EDT
But you do feel it was one or the other?  I would like to hold my landscaper accountable for this as he has been very distant about the situation. I would just like to understand if I have grounds for this.  
 Thank you again for your response as 

On Fri, Jul 5, 2024 at 3:15 PM Ask Extension <<personal data hidden>> wrote:
The Question Asker Replied July 05, 2024, 4:46 PM EDT

I can’t give you a good answer to that question. What was there before you hired the landscaper to lay sod? Did they scrape the area clean before laying the sod? Did they use any weed killer prior to laying the sod? 

You will have to have this conversation with your contractor.

Deb Reierson Replied July 06, 2024, 6:21 PM EDT

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