The dollar weed is the one you have worry about first. There are three kinds of plants that grow in lawns. One is classified as grass or your target turf grass (these include common lawn grasses like turf type fescue, Kentucky bluegrass, St Augustine, hybrid bermuda, centipede, zoysia). Another is broadleaf weeds (clover, dichondra, pennywort, spurge, horse herb, black medic, creeping charlie, and others). The third category is grassy weeds which do not tame well (sedges (nutgrass and ), Johnson grass, crabgrass, common bermuda, barnyard grass, annual bluegrass, goose grass, and others). The broadleaf class of weeds are the bane of St Augustine lawns because they will easily shade out new growth. The St Aug will thin out fast and disappear in just a few months. With grassy weeds, the coarse blades of the St Aug usually shade them out. Fortunately there are different kinds of chemicals which kill the different kinds of plants. Broadleaf weeds are killed by the 2-4,d chemicals in Weed-B-Gone. Unfortunately St Aug is sensitive to 2-4,d also. Most plants are killed with atrazine but St Aug is not. I have not heard of penoxsulam, but then I don't pay much attention to herbicides. There is also Grass-B-Gone and Sedgehammer for the other weeds. Again, unfortunately, lawn grasses are killed by the Grass-B-gone product. The one good herbicide specialist is Sedgehammer. You might try the penoxsulam in a small spot as a test. Otherwise look for something with atrazine. Occasionally you see it as I described above. Your middle picture looks like crabgrass compared to St Aug, but it is the wrong time of year for crabgrass. I'm going with centipede. It looks like St Aug in many ways but it has pointy blades where St Aug has a boat-tailed shaped blade at the end. Simply taking care of the lawn with water and fertilizer will kill the centipede. Here is a picture of the two grasses. Then the prescription is to get a broadleaf weed killer that is safe for St Aug. My comment about this not being the time of year to kill weeds has to do with the plants not being in a fast growth state. You can try it. It could be your area is warm enough that everything is growing. I would fertilize with organic fertilizer, wait 3 full weeks, and then spray. You want the weeds to be growing and healthy before spraying. In the mean time raise your mower all the way up and weld it in place. There is never any reason to mow St Aug lower than full height. And keep the water off as much as you can.

I have Floratam - mid Florida. My initial Spring shot at the weeds is with Scotts Bonus S. - my first appplication of fertilizer. Later I use "Image for St. Augustine Grass and Centipedegrass with Atrazine." It requires several days for the weeds to go away but it has been pretty effective. Some weeds like Dollarweed do not completely go away but the Image helps to control it. Big box stores such as Home Depot have it. You should read the label - open up the sticky thing on the back to get to see all of it.

Sorry. This will be a long one. It always is with me. (blushing) I'm with the OP on this one. Even if no one but me ever saw my lawn, I would want it to be dark, rich green GRASS...and nothing else. (I'm known for wanting everything to be beautiful. I'm also a bit of a home body, and enjoy spending time in my yard. Many guests have remarked that, no matter where they look (on my property), there's always something beautiful. I'm always taken aback by those comments, since while that was MY goal, I never expected others to pick up on it.) Case in point about the intentional act of putting down grass, and not other (lower maintenance) plants. I own a small, remote island. I made the decision to create a lawn area and, once you include the slow-moving barge fees (3 days to get from its port to the island), labour, equipment, and materials, that lawn cost me $14,000. That obviously begs the question, why, on earth, would anyone spend a nickel putting in expensive, high-maintenance grass, only to let it be taken over by clover and other weeds??? My husband and I recently purchased a 19th century farmhouse in need of roof-to-foundation renovation. As such, I inherited a lawn that is EASILY 70% weeds, including clover so thoroughly interwoven, it would be impossible to pull by hand. I pride myself on my beautiful lawns and gardens, and can spend/have sent hours, each day, ensuring everything is healthy and how I want it. At my last home, I developed a bit of a reputation for being out weeding my lawn by hand for hours, plus how awesome my expansive lawn was. My point is, I want my lawn and gardens to be a certain way; plant the plants I want; pull the plants I don't want; unafraid to put-in the effort to achieve that. I prefer not to use any kinds of "chemicals", other than the ammonia and mild soap I include in my homemade fertilizer recipe. (My last home was a beach house. So, that only reinforced my desire to go chemical-free.) But this new-to-me house is demoralizing me...practically to the point of tears, much of it because of the state of the (laughing) "landscaping". Sure, mowing can cut off 60% of the sea of clover flowers that make my lawn look white (or dying...can't decide which). But there are still lower flowers that seem to sprout up to full height within the next 24hrs after a mow. These flowers last from late spring to fall. In short, I'm plagued by clover flowers throughout the entire season I want my lawn to look great. It's just such a shame the previous owners didn't nip the clover in the bud, when each plant was jut a little, round cluster. I love catching them early, knowing I've stopped additional infiltration. But I'm helpless, overall. Looks like I'll have to replace the entire lawn; start from scratch; do what the previous owners SHOULD have done, and pulled weeds when I first see them. I'm not really buying the whole "benefits of clover" thing, amidst a grass lawn. If I wanted a clover lawn, I would plant a clover lawn. Putting down and maintaining grass is an expense in time and resources. Clover is virtually free (since it shows up on the wind), and is seemingly mantenance-free. Since most sod and grass seed are sold with some guarantee of being weed- (and clover-) free, I just don't believe that most people who spend the money and effort to put in a grass lawn, are okay with losing any percentage of it to other, invasive, undesirable plants. I kind of liken it to suggesting that a Ferrari owner would be okay with someone switching it with a Cavalier, and just saying, 'They both get me from point A to point B, so I don't mind.' I can fully envision putting in other kinds of ground cover, and have considered it at past properties. Not being my first rodeo, I already have substantial plans to reduce the amount of lawn area, and increase planting beds. But much of this current property begs for a beautiful, thick, dark green lawn...of grass. No dandelions. No clover, but particularly no clover flowers. (I'd be more okay with clover, if not for the flowers.) The desperation was so great, I did something I thought I'd never do, and tried the iron-based WEED-B-GONE product. (Harsh, chemical herbicides have been banned in my area for years...resulting in public parks being taken over by weeds, for the most part. It's such a shame, in the sense that a healthy, well-maintained lawn is not only beautiful, but fantastic underfoot.) That is really my philosophy, beyond the aesthetic. A lawn should be cool, soft, and luxurious under bare feet. Weeds, even overgrown grass, also tend to make barefoot walking less than a joy. So far, I haven't found a way to get rid of mats of clover. The WEED-B-GONE did nothing I could notice. I'm at my rope's end on ths matter, and likely will have to pull up the entire lawn, to put down new, almost-weed-free sod, where I can physically manage pulling individual weeds as they appear. I guess I'd plead with people to pull unwanted clover plants when they're small... if not for yourself, then for the next property owner. Sure, it means time, every day, or every few days, combing the lawn, looking for weeds. Yes, it can be back-breaking and time-consuming. But that grass lawn didn't get there by accident. A grass lawn is intentional.

Creeping Jenny is an incredibly difficult weed to get rid of. Fortunately, clover and most others are a lot easier. Weed B Gon with Chickweed, Clover, and Oxalis Control will take out the vast majority of weeds that you have. If it's really infested, you might want to blanket spray the first time. Post that, I'd use a hand-held pump sprayer to treat individual weeds. That way you aren't stressing the grass with weed killer, nor throwing it around where you don't need it. For Creeping Jenny, keep pulling it. It can take years for the root systems to finally die. Apparently, some people have had great success with Trimec herbicide sprayed about six weeks apart as well, so you could try that. Trimec is available at most big box stores. Post the weed kill, I'd mow your lawn as tall as you can stand it. That'll tend to shadow out new weeds. Also, if you could let us know how (and if) you feed and water your lawn, those have a direct impact on whether weeds flourish or not.