# NJ grassy weed



## devanb (Apr 26, 2020)

Just came back from a week vacation on NCL and my fall renovation areas are absolutely awful!



I used jonathan green but I'm not even sure if that was the issue.

I did put down a preemergent Pridiamine WSG on 3/18/22 but my landscaper did a core aeration without me knowing about it on 3/31. The grass in question grows more vertically than crabgrass (IMO).

Can you help identify this light, fast growing grass? I can't decide if its K31, nutsedge, or poa trivialis. There are seed heads. I'm holding off mowing them down until I hear back.







Thank you!


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## devanb (Apr 26, 2020)

One more image to help ID


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## devanb (Apr 26, 2020)

Well, I guess I'm not the only one to get stumped.

I sent an email to the seed distributor for their insights. My soil analysis demonstrated low potassium so maybe this is annual ryegrass with some chlorosis?

Anyway, I stopped pulling it, mowed it and am going to apply some liquid potash.


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## 2L8 (Mar 18, 2019)

The spikelets appear to have awns. Therefore, tall fescue, nutsedge and Poa trivialis are ruled out.

Is the grass hairy? Then it could be wall barley (Hordeum murinum). But the flowering is a bit early and the color too light green.


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## devanb (Apr 26, 2020)

its not hairy. If you want a more specific photo, I have hundreds of specimens! let me know if I can aid this somehow.


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## 2L8 (Mar 18, 2019)

devanb said:


> its not hairy. If you want a more specific photo, I have hundreds of specimens! let me know if I can aid this somehow.


Another suggestion: tall (false, bulbous) oat grass (Arrhenatherum elatius, onion couch). This has light green leaf blades, but they are slightly hairy on the surface (magnifying glass). The underside is glabrous. The ligule is often fringed and the leaf base is wavy (images at Wikipedia, https://en.wikipedia.org/wiki/Arrhenatherum_elatius). The granule has a kink.

The grass develops strongly already in spring, which would fit, but here the flowering begins only in mid-May. I saw that you already had a few days above 70 °F in mid-April. Maybe that triggered the flowering.


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## 2L8 (Mar 18, 2019)

My estimate of the bloom time may not have been entirely correct. Here, too, tall oat grass already begins with panicle pushing. Until the flower is fully developed it may still take a while. One more point in favor of tall oat grass.

Here the stuff grows in many places at the roadside. I took a closer look at one plant today:


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## devanb (Apr 26, 2020)

that looks very similar.  I covered the areas with hay. perhaps a contaminant.

Do you know if its a perennial or annual?


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## 2L8 (Mar 18, 2019)

It is, unfortunately, perennial. Moreover, it is said to form deep roots and rhizomes. So try to get rid of it as far as possible. Pulling it out or better levering it out should still be possible.

The grass was not native here originally. It is said to have been introduced in the 19th century. Now you see it in masses at the roadside. Apparently a very invasive neophyte.


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## devanb (Apr 26, 2020)

2L8 said:


> It is, unfortunately, perennial. Moreover, it is said to form deep roots and rhizomes. So try to get rid of it as far as possible. Pulling it out or better levering it out should still be possible.
> 
> The grass was not native here originally. It is said to have been introduced in the 19th century. Now you see it in masses at the roadside. Apparently a very invasive neophyte.


Thank you for the help.

After much searching and sampling, I think I have Cheatgrass, Bromus tectorum. The seed head most closely resembles what I see online.

I've been hand pulling these plants for a few days, about 200 so far. There are thousands so I'm stopping.

I plan to put some preemergent again in the spring, and this fall and keep mowing. Hopefully it's cheatgrass and its an annual.


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## 2L8 (Mar 18, 2019)

Bromus tectorum we can rule out as this grass is hairy and yours is hairless. The leaves are narrower with a maximum of 1/4 " in cheatgrass.

But your guess alerted me to the fact that cheatgrass is a very invasive grass in the US (especially in the southwestern states), which is not the case here in Europe.


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## devanb (Apr 26, 2020)

On closer inspection (taking off my glasses) the grass is definitely hairy.

Sorry I misled earlier.


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## 2L8 (Mar 18, 2019)

Sorry for the late response. But if the hairs on the grass are only noticeable on closer inspection, then oat grass is more likely to be considered. Cheatgrass has longer hairs and the leaf sheath is also very hairy there.
Oatgrass:

Cheatgrass:
https://www.eeob.iastate.edu/research/IowaGrasses/speciespages/BromuTecto/BroTecLi1.html

From a distance, however, both grasses are surprisingly similar.

In the end, however, both grasses can probably only be removed by pulling them out.


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## devanb (Apr 26, 2020)

If it is cheatgrass, an annual as I understand, then it should die off this year. I am applying preemergent in the fall this year since I am not seeding (ever again).

The samples I photographed were quite young. The plants now are definitely hairy.

Since I was planting on a steep incline, the brome actually helps to stabilize things. I'll keep posting on this thread in case anyone else ends up growing hay after a renovation.


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