A: Let’s properly identify this plant first. Given the lime green color, and the fact that the listener said it is easy to pull up, I believe this is nutsedge. Mondo grass has a darker green leaf, different seedhead than the one pictured, and doesn’t pull up easily due to it’s clumping habit.
Nutsdege is a bear of a weed to deal with. Traditional, broadleaf herbicides don’t work real well on it. Since it’s easy to pull up, start with that. Manually remove all of the plants you can before these seedheads mature, fall and spread.
Yellow nutsedge is actively growing in the summer, and targeted herbicides are best applied this time of year. Don’t apply to dry, drought-stressed lawns. You may want to water the day before in order to protect the turf. Also, avoid applications during hot or dry weather to minimize injury to the turf as well. Image, Sedgehammer and Bonide’s SedgeEnder are just a few good herbicides - Image, however, is not recommended for use on tall fescue.