Wow. While dsnell's plan might work for someone, most all of it has been discredited by the masses on these and other forums over the decades. Although I agree that weed killer is a harsh treatment, sometimes it's the only thing that works. And fertilizer does not take the place of weed killer. If fertility is low on a sod-forming type turf, then fertilizer can sometimes create a more dense turf that resists weeds. March is generally 3 months early to fertilize. You would be fertilizing the spring weeds. Weed n feed products are difficult to apply properly and they are not built with Mother Nature in mind. The time to kill weeds is in April. The time to feed is late May. WNF is a product that sounds too good to be true. Adding topsoil is almost never a good idea unless you have a low spot that needs to be filled. The rye and fescue grasses recommended will never work on half the country. I agree that watering every day is incorrect, but so is watering every other day. I water every 1-2 weeks and have a green lawn all summer. Finally, only apply lime if you have a recent soil chemistry test that shows low calcium and follow the recommendations for the specific type of lime and amounts.

I didn't try to change your words or significantly twist what you had to say, and I don't see why you felt the need to do that to my post. I'm not at all clear on how I am twisting your words. It was not clear that you were suggesting glyphosate/RoundUp in place of the Spectracide....sorry if I mistook your intent, but I assumed we were all taking about the OP's product. That WAS the question, afterall..... Apparently, you didn't even really read what I wrote, because, if you did, you are intentionally trying to confuse the nature of what I wrote to support your position. Oh, I read it! And you very clearly stated that the stuff is "100% safe" and "is not known to translocate between different kinds of plants". I merely pointed out that this position is not supported by a significant amount of scientific evidence. And in refutation you said you have seen no "credible" evidence to support this and "famous people in the know" say it can't/doesn't happen. But you gave no cites to support this statement, whereas I provided several to support mine. How "famous" the authors of these articles are, I have no idea, but they are qualified and trained scientists and they do support and document their theses with various other, equally well-qualified sources. What I wrote wasn't just my opinion. It's the conclusions drawn by many (the vast majority, that I've run into) professionals and educators that study herbicides. But you neglected to provide ANY cites or documentation to support that it was anything more than just your opinion. And what exactly constitutes the 'vast majority'? Five? Twenty-five? Fifty? You provided none. What's more, you clearly stated that in your "opinion most of the material is not relevant to this situation". Yet you don't bother providing anything other than your 'opinion' to support this statement nor do you give us any reason why your 'opinion' should necessarily be held in greater value than those scientists whose work I reported. Maybe you have some detailed scientific background that we are not aware of? BTW, the emoticons that you, specifically, seem to always use to "disguise" obnoxious and rude comments, don't really do the job. For me, they kinda did at first, but the pattern in which they repeatedly show up in many of your posts (after rude comment, after rude comment, after rude comment), has made their real meaning evident and even seem to amplify and call attention to the cheap shots. I was attempting to keep the tone rather light. Apparently I failed. I am well aware of your propensity to refute or argue against everything I say and was trying quite hard not to become unnecessarily adversarial. As to cheap shots and rude comments, you dish out your share, fella! I'd offer the above as ample evidence. It is almost as though you cannot tolerate someone else offering another differing, yet perhaps just as valid, viewpoint. And if I were a little less secure of my experience and knowledge base, I might even go so far as to say that the possibility of a mere female having the temerity to question your apparently sacrosanct opinions/viewpoints pisses the heck out of you. Been there, done that......doesn't bother me a bit. But all of this is really immaterial to the OP's initial question and not furthering the discussion in any positive way. I've said everything I need to say and I stand by it, so if you feel you need to run me down any further, have at it.

Unfortunately, nothing so completely selective as you may wish. Broadleaf herbicides will target the weeds, leaving the grass and liriope. Grass herbicides will target any monocot and that includes the liriope as well. Often when weeds and especially grassy weeds get such a good foothold, it is best and most efficient to dig up the entire planting, remove the weeds and grass roots from amongst the liriope and then replant. I'd wait until a bit later in the season, though.

If this is indeed weed-killer damage, those work by putting them on green plant which carry the poison down to the roots, with the intent that they don't grow back. Time will tell. It could be an infestation of the roots by a bug of some sort. In that case, take a sample (with leaves, stems, roots in a sealed baggie) to your county extension service (find that service simply by typing "county extension service" with your county name into a search engine. If it does not spread into the reset of the lawn, this could be an opportunity to do something interesting with that front portion of the yard, such as an undulating delineation with the same cobbles you have at the back of the lawn, plus gravel and desert plantings that will thrive in the reflected glare off the sidewalk. It could make your house feel a bit further back from the street, too. It would require removing the dead sod and laying down a weed screen, and adjusting the irrigation so you don't drown the new plantings. Good luck figuring this out and coming up with an attractive solution that you'll be glad to come home to every day!