It looks like a type of Nut Sedge. Yellow nut sedge is the most common in home landscapes in Maryland. Sometimes if they are immature they haven't formed a 'nut' yet.

It can be difficult to remove but with persistence it can be done! You can try to use an herbicide specific to nut sedge like Sedgehammer. You may have to reapply as it returns. Just be sure to follow the label directions. You can also try to dig up the area and remove any or the pieces of rhizomes or 'nuts' you may find. It will inevitably return so if you just keep pulling or digging as they come, eventually you will exhaust the root supply and they will die. 

If you can improve the drainage if its a wet area that can help as well. 

You can reference our fact page on Nut Sedge for more information and tips on management. 

Let us know if you have further questions. 

Emily