A: This sounds like nutsedge, and it’s a persistent weed in the flowerbeds and lawn. Pulling it does tend to make it worse! Nutsedge has a thin root system connecting large, nutrient-filled nodules. When pulled, each individual piece of nutsedge comes up easily as the thin roots break, but each of those nodules will sprout new leaves in short order. You need a nutsedge-specific herbicide to control this weed.
In the lawn and around (not on!) established, woody ornamentals, we recommend Sedgehammer Plus herbicide to kill the nutsedge. And be patient. Sedgehammer can take two to three weeks to work. Wait for full effect, then spot treat any spots that weren’t sufficiently controlled with the first application. And as a quirk specific to this herbicide, agitate (shake or stir) the spray tank periodically while you spray to keep the herbicide effective instead of coating the sides of your tank. It’s suspended in the water you mix it with, not dissolved.
And save yourself time and frustration. Don’t pull nutsedge. Unless you dig up every single starchy nodule, it’ll come right back.