I'm dreadful at this, but it's a broadleaf. :-) It looks like Weed B Gon will take care of it without doing damage to the surrounding lawn (I tend to just head straight for the Weed B Gon Chickweed, Clover, and Oxalis as it's wider-spectrum).

Your lawn looks like a standard tri mix, but if you could let us know your state and nearest city, we can give you a pretty good guide for when to do what with what.

And frankly, I'm far enough off-kilter tonight I might be misreading Bermuda as bluegrass, too. :-)

I'm guessing southern state with a mix of bermuda and St Augustine along with the weed and live oak leaves. We defs need to know where you live and your grass type(s). If you have St Aug and you want to keep it, you should not use normal Weed-b-Gon.

Any chance you accidentally spilled arugula seeds, and then forgot about it?

We are in Gainesville, Florida! Mixed reviews on whether to use Weed B Gone I see...

Don't, not in Gainesville, I was clearly having a stroke or something. Whatever's rated for southern lawns would be appropriate.

Mixed reviews is sometimes the case when we don't know where the lawn is nor what kind of grass it is. There are several WBG products for use in the north and only one for use in the south and then only on bermuda. If you have St Aug and want to continue with that, then an atrazine product would be the way to go. Atrazine won't really hurt the bermuda even though it is not supposed to be used on bermuda. However, St Augustine will dominate over bermuda when you mow at the mower's highest setting and stop fertilizing the bermuda.

Here is the atrazine product I use. I like the hose end valving.

If you use an atrazine product, limit yourself to no more than 2x per year. In Gainsville you can probably spray it now and again in September. You only have to spray the weeds and you only need to moisten them. It is not a soil drench product. Also walk backwards and upwind so you don't have to walk through the wetted grass or get sprayback on you.

Thank you all! How do I figure out what grass I have? Sorry, total novice here.

Bermuda grows from runners across the surface of the soil. It has very fine blades with pointed tips. St Augustine also grows from runners across the soil. It is a coarse blade with a blunt end on the blade. The best way to see what you have is to compare to other pictures. Here's a Google Image search for bermuda grass. And here is a search for St Augustine grass. Let us know what you have and we can help you make it nice. Do you have pets or children playing on the grass? What about shade?

All grasses need water, mowing, and fertilizer. If you are doing those things right, you should only need a minimum of herbicide and hopefully never insecticide or fungicide. We can get into more detail after we know what you have.