What is this?

[cleavens15]

Hello,

Planted tall fescue in my yard two weeks ago. In some areas, it has been growing beautifully. In others, there are patches of something short with a rounded head. They're bright green.

Any idea what it is?

 

[Oliver Buckle]

They look like seed leaves, which are all pretty similar. So many so close suggests something like bitter cress producing a lot of seeds in one place.

 

[cleavens15]

So, is it a weed? Is it harmful?

It is difficult finding information online about it.

 

[Chuck]

So, is it a weed? Is it harmful?

It is difficult finding information online about it.

At the moment it is extremely difficult or impossible to say exactly what this is. What you see are called cotyledons. They are the embryonic leaves of a plant and usually look nothing like the mature plant. Just give it a little time for the first set of true leaves to form to find out what it is.

 

[Oliver Buckle]

" Just give it a little time for the first set of true leaves to form to find out what it is."

On the other hand you can do what I would and say, "I planted fescue, it is not that, it is not what I wanted, and even if I like it it is in the wrong place, that makes it a weed." Then I would rub it out while it is still young, tender and vulnerable and plant some more fescue.
Anything that grows that thickly, and you didn't plant, is likely to be a weed that produces an awful lot of seeds. Weeds can develop and flower very quickly, run a hoe over any patches like that and they become green manure for your grass.

 

[YumYum]

I'm gonna guess and say it is clover.

 

[Tuilly]

This looks like clover but not clover.

 

[cpp gardener]

I side with Oliver for the reasons he stated. You didn't plant it, it's not what you planted and it could take over. Kill it and be done.