You're overwatering for this time of year...or any time of year. This time of year you should be watering once per month and applying a full inch when you do. 12 minutes is likely not a full inch. With my sprinklers it takes 8 hours to get an inch. My neighbor gets an inch in 20 minutes. You'll have to measure yours - with cat food or tuna cans. In the hottest heat of summer you might need to go to once every 5 days but once every 7 days is usually all you need. Also raise your mower to the highest setting for St Augustine. You never need to lower it. It will take a few weeks for all the grass to get up to that tall, but it will be worth it. Your dead grass is from a fungus from over watering. I use ordinary ground corn meal to kill disease in my St Aug. It works every year for me. Your dollar weed needs a spray specifically made for St Augustine. There is a black bottle with a purple label at Walmart. Sorry I can't remember the brand (maybe Spectracide). That should work and not damage the St Aug too much.

Sorry for the delay getting back. I have a vacation condo in Rockport so we have been dealing with hurricane debris and salvage. The initial problem was improper watering. When roots get a fungus and rot away, the plant above dries out making it look like it is not getting enough water. Truth is the plant is not getting enough water, but the cause was too much water. Watering dead roots doesn't fix it. At this point you have to hope some of the roots were not completely dead and will return once things dry out. Adding fertilizer stressed the situation rather than fixing the situation. Of course watering after the fertilizer was necessary to dilute the fertilizer, but the yard already had too much water. What I would do is to buy a bag of ordinary corn meal at your local feed store (call around for availability). Scatter that at 20 pounds per 1,000 square feet. And don't water it in. If the soil has already dried out and the corn meal does not start to look gray in a couple of days (a good sigh of decomposition), then lightly spray over it with a hand held spray nozzle. All you need to do is moisten the corn meal. Corn meal will help feed the soil microbes and, hopefully, kill the disease microbes causing the roots to rot. If you don't see any green up after 3 weeks, then the lawn is likely dead. I would not water it again for at least a month to be sure the soil is drying out. Here is some information about deep and infrequent watering. Watering: Deep and infrequent is the mantra for watering. This is for all turf grass all over the place. Deep means 1 inch all at one time. Put some cat food or tuna cans around the yard, and time how long it takes your sprinkler(s) to fill all the cans. Memorize that time. That will be the time you water from now on. My hose, sprinkler and water pressure takes 8 full hours to fill the cans. Your time will likely be less. I like gentle watering. As for watering frequency, that depends on the daytime air temperature. With temps in the 90s, deep water once per week. With temps in the 80s, deep water once every 2 weeks. With temps in the 70s, deep water once every 3 weeks. With temps below 70, deep water once a month. Note that you have to keep up with quickly changing temps in the spring and fall. This deep and infrequent schedule works in Phoenix and in Vermont, so it should work for you. The reason for deep and infrequent is to grow deeper, more drought resistant roots and to allow the soil to dry completely at the surface for several days before watering again. If it rains, reset your calendar to account for the rainfall. That is what you should have been doing instead of watering every other day. In Houston while the climate is unbearable in the summer, the problem is humidity and not the actual heat. Humidity keeps the water from evaporating, so rather than watering once a week, you might be able to water deeply once every 10-14 days in the summer.

What I know as blue star creeper is an entirely different plant, Isotoma fluviatilis. It is an extremely popular groundcover here, as it is easy to grow, holds up well to foot traffic and has long bloom season. It is an excellent lawn substitute. I've not known it to get out of hand and invade lawns but I suppose it is possible. It also doesn't look much like what it is in the photos, as it is very mat-like and flat. I am also not the slightest bit obsessive about a lawn being 100% turf grass. Monocultures are never ideal and I much prefer a mix of various creepers, wildflowers and yes, even weeds in my lawn areas than doing battle with chemical warfare to get rid of what wants to grow there naturally. Turf grass lawns already suck up vast amounts of natural resources and chemical products as it is. Before you opt for whatever herbicide is your choice, confirm the ID first.

Yeah, I can already hear the excuse coming because if I didn't know what happened, I would have pronounced it dormant. due to the location and visual from a distance. Unfortunately, proving that will be almost impossible. Most herbicides can and will burn the lawn if the temperature is above 80-85 when applied and in sunlight (and blanket spraying is not recommended at any time unless the problem is also very wide-spread). You know that now...they should have known that, but, as Sherry noted, they had a timeline and probably a boat payment to make. Spot spraying herbicides later in the evening can be OK if you know your lawn is up to it. But that's only true on established lawns, is very herbicide-dependent, and not something I'd do over a wider area. I did it on my own a few days ago in two tiny areas of less than a square foot to remove a piece of nutsedge and a tiny bit of creeping Charlie that had gotten started in a dormant bit, but I was very careful not to overspray and I was using an herbicide that's not particularly known to cause damage even in heat. The good news. Some of that is going to recover because it's top burn. The blade and crown burned, but from the before shot, the grass very clearly has lots and lots of carbohydrates stored in the roots to use to regrow the crown and blade. That does take a lot of energy, and some time, but keep that watered and it should work. The bad news: These idiots managed to hit this at, quite literally, the worst possible moment on the calendar when carbohydrate reserves in the roots are at their lowest point, so some of it is NOT going to recover. I can't see the grass type at this distance (and I'm pretty visually disabled so have trouble with plant ID even up close sometimes unless the color stands out), but hopefully at least some of it is Kentucky bluegrass. Bluegrass spreads when well-fed, so your Labor Day feeding will encourage that to fill right back in. First, fire them. Or restrict their care to mowing it if they do that. Taking over your own care is very easy if they won't do it right. Second, water. Keep the soil damp to moist for a week or so in the burned area to see where you are, if rainfall doesn't do it. Just moist, not wet or soaked or squishy or puddled or... This is the one case where I'm actually going to recommend shorter, frequent watering. Thirty minutes, every other day? If it works to keep it damp, sure. But just for a week--we do not want to set off a fungal infection in that yet and the lawn is stressed. Cut it off dead after that and resume weekly watering unless... Third, seed. If you're really not seeing recovery when you spread the dead stuff and look down, you might want to reseed. Normally I'd give it longer, but you're on the clock here, and Labor Day is really the outside acceptable date for reseeding (you could re-sod that area much later, however--out to about September 20th or so). If it comes down to that, get back to us. There's a whole rigmarole for that. And for general lawn care if you choose to do it yourself--it's pretty easy--or just dictate what they're going to do in the future (which they usually will disobey because...hey--boat payment). Watering: Weekly, deeply, if rainfall isn't doing it, a full inch at a time in most soils, but there are some exceptions, a very few. That's the general rule, although during very hot periods, you can certainly nudge that down to every 5 days or so and I won't argue. (How do I do it personally? I don't water. My bluegrass lawn is allowed to go dormant and return when rainfall returns, but it's fully mature and healthy enough that this is not a problem). Feeding: Four times yearly (three can be acceptable). Memorial Day, Labor Day, October first, and when the last mow of the year is done, give or take some. The first three can be organic or synthetic, the last has to be synthetic. Either one of the last two is optional as long as the other is done, so a very cold year may end in October, or a year where you're not sure may end with delaying October's feeding but doing the shutdown feeding later in October or early November. For Maryland (and up here in PA), both can almost always get done as even December features green grass these last three decades. Weed and Feed: Never. It does neither job well as the appropriate weeding time is not the correct feeding time. Spot spray weeds, if any, as they appear. Try not to apply synthetic feeding to a damp lawn as it can burn the lawn--which is how Weed and Feed is supposed to be applied. Really, once established and healthy, lawns are mostly butt work. You sit and look at it because it mostly does its own thing. Those two weeds are the only two I've sprayed all summer, and they're only there because the lawn is partially dormant and rains just resumed. If I'd ignored them, the sedge would have grown, but the Charlie would get choked out.