# Grassy Weed or just grass?



## Alowan

Hi. Long time lurker but first time poster (have to do a lawn journal after getting way into lab care)

I have a grass in my lawn that I don't know if are a weed or are grass growing clumpy for some reason.

My lawn was established last fall and had a huge dieback this spring so I just recently did a spring renovation and overseeding. (Established and overseeded with ryegrass, RPR and red fescue.

It is looking okay but I am seeing these clumpy tufts of grass throughout the lawn. They lay flat and grow flat out from the center. They seem to block growth around them and not grow as much laterally as the rest of my grass.

Any ideas what it is and how to fix it?

Overview:



Before "collecting it":



After clumping it together: notice lack of growth around it:





Same plant in newly seeded part / seems to grow extremely fast.


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## Adamg77

Has it out any seed heads out?


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## Spammage

@Alowan looks like either poa annua or POA trivialis.


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## Alowan

Lots of seedheads - but I think it might be season for that (even though none of the lawns around kurs Seem ro have gone to seed (but 70% of mine has)

The last image has been confirmed to be trivialis. However it looks different than the first one. The first one I am unsure of. Could be annua. However it dosent Seem to be annual…


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## Alowan

The biologisk who identified the trivialis Said it might be a KBG but Was unsure.


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## Alowan

And Ryan Knorr adresser the seedheads in his latest video. Semisure what I have is *** seedheads (which is interesting afaik I did not seed *** last year)


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## Alowan

After letting it grow for a few days There are seedheads everywhere. Semisure it is majorly infedted With poa annua. Sad.

Might have to kill it and redo.


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## Midsoutherner

That looks like POA annua. How hot does it get in Denmark in the summer? Poa Annua will die off in high heat, but you will need Pre Emergent to keep it from coming back next year, or getting worse.


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## Alowan

Midsoutherner said:


> That looks like POA annua. How hot does it get in Denmark in the summer? Poa Annua will die off in high heat, but you will need Pre Emergent to keep it from coming back next year, or getting worse.


Around 25-28 degrees C / 80-82 F

It dosent Seem to die off atm. And PreM are not an option due to regulations kn what a home owner/ amateur Can use. So contemplating on what to do.. made things worse by scalping everything to remove the seems and er have a heatwave atm… #facepalm


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## Midsoutherner

@Alowan Could you pay someone to handle the PreM for you? With a smaller yard it may not cost too much to have just that done 2 time a year, but of course that won't get rid of what is already there. Unfortunately I think that most of the post emergent herbicides that will kill poa will also kill your rye grass and possibly the fescue too. I don't know a lot about weed control in cool season grasses, so I can't be more help.


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## Alowan

Midsoutherner said:


> @Alowan Could you pay someone to handle the PreM for you? With a smaller yard it may not cost too much to have just that done 2 time a year, but of course that won't get rid of what is already there. Unfortunately I think that most of the post emergent herbicides that will kill poa will also kill your rye grass and possibly the fescue too. I don't know a lot about weed control in cool season grasses, so I can't be more help.


Really great idea - unfortunatly it is not allowed on personal/home lawns. Could get some from a farmer etc - but applying it is illegal.


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## Alowan

Even With the Sun basing the grass seems relentless. Could it be poa pratensis and not annua?


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## Midsoutherner

I didn't realize you meant the PreM can't be used at all on residential lawns. I thought you meant you would have to hire someone who is licensed to spray it. I don't want to suggest you do anything illegal.

The Poa I had in my backyard didn't die off until after I sprayed it with Certainty, and the temps were consistently over 85 degrees. It died real fast after that, but I'm almost positive you will kill all of your grass with Certainty.

You may have to either start over, or possibly continue to over seed with more of the grass you want in the yard to hopefully choke most of the Poa out, which to me sounds like the better option. Also mowing higher will help to choke it out too.

I found a short article, here, that may help identify which of the two grasses you have. From what I have gathered from looking around online the KBG seed heads are much more dense with seeds vs the Poa annua.

If you haven't looked at this list yet, I would also.


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## Greenlawnman

Can some help on identifying these ?

I believe it is Poa Annua but not sure. I have Kent Blue Grass.

See pics.

Pls help.

Thx


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## Alowan

Midsoutherner said:


> I didn't realize you meant the PreM can't be used at all on residential lawns. I thought you meant you would have to hire someone who is licensed to spray it. I don't want to suggest you do anything illegal.
> 
> The Poa I had in my backyard didn't die off until after I sprayed it with Certainty, and the temps were consistently over 85 degrees. It died real fast after that, but I'm almost positive you will kill all of your grass with Certainty.
> 
> You may have to either start over, or possibly continue to over seed with more of the grass you want in the yard to hopefully choke most of the Poa out, which to me sounds like the better option. Also mowing higher will help to choke it out too.
> 
> I found a short article, here, that may help identify which of the two grasses you have. From what I have gathered from looking around online the KBG seed heads are much more dense with seeds vs the Poa annua.
> 
> If you haven't looked at this list yet, I would also.


Thanks for the excellent reply. I know that noone wants to suggest something illegal - and it is really hard to know the rules of every place 

I have narrowed options down to two things (with a start point in 2 weeks - so have to decide before then)

1. If I conclude that there is too much poa and a redo is needed. I will start sorting glyphosate in 2 weeks and fallow to prepare for a complete Reno in august. Then use RPR and poa patensis mix from Barenbrug that shouldestablish fast and potentially fight poa in the long run. A small test I am doing is looking promesing however I won't know how a few seasons will impact it.

2. Due to the relative small size of the lawn I have tried to spot treat and pull the poa. If I go this route I will spot treat/pull as much poa as I can. This will leave a lot of holes that I will seed in august with my current RPR and shade mix. + I would try a SUper Over Seeding in the winter to see if that combats the poa.. (locking me at min 20mm HOC)

I am still really unsure what route to go as the poa seems to be the same green as my other grass and the fact that without a PreM it might come back just as bad (however my skills have improved so the seeding/Reno should go better).

Any suggestions/input are most welcome!


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## Thejarrod

please keep in mind that the Poa annua seeds that are currently on the stems or already in the soil will continue to germinate after using glyphosate. Fallowing will take care of weeds that germinate...but all the seeds won't immediately germinate so its hard to get them all.

Poa annua pulls out fairly easily, so i would suggest that route for that small space.

sorry that pre-emergent herbicides are not available to you.


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## Alowan

Thejarrod said:


> please keep in mind that the Poa annua seeds that are currently on the stems or already in the soil will continue to germinate after using glyphosate. Fallowing will take care of weeds that germinate...but all the seeds won't immediately germinate so its hard to get them all.
> 
> Poa annua pulls out fairly easily, so i would suggest that route for that small space.
> 
> sorry that pre-emergent herbicides are not available to you.


Thanks for the answer. I am leaning that Way and stressens the Poa as much as I Can. Only reason for nuking atm would be to lower the poa amount so hand pulling dosent mean pulling the full plot and to change the seed (The lawn Was seeded With a good but not elite seed and have been oversendes With elite seed - I would use this to change to just one mix)


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## Alowan

At what point is killing the lawn and pulling poa the same thing


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