Good pictures. Thanks. The weed in picture number three is called horse herb. If you are simply interested in green, that can be it's own ground cover. If you want a lawn; however, that HAS to go. I'm curious where you are from that you think seeding is the thing to do to establish a lawn? In the south it is mostly done from sod. If you are putting in some trees, that eliminates all the southern grasses except St Augustine. If you have more time than money, you can spend $5 on St Augustine sod and place those pieces around the yard. St Augustine will spread out about 10 feet per season and eventually cover the entire yard. $5 worth of St Aug sod should be at least 3 pieces. Start by clearing some spots for the new sod. Carve it out about 3/4-inch deep to allow for the new soil on the sod. Place the sod and start to water it daily. Only water the sod and only enough to moisten the sod - no need to drench it soggy. Do it 3x per day (breakfast, lunch, and dinner time). Continue that watering for 2 weeks until the sod roots have knit into the underlying soil. Then start to back off on watering frequency. Avoid watering the rest of the yard to help keep the weeds down. Since you're in Austin I'm going to assume you will be okay with organic fertilizer. I would start with two heaping handfuls of alfalfa pellets (rabbit chow) per piece of sod. Buy it at your local feed store. Two handfulls is a lot, but it can take it all. Do that monthly to get it going. Moisten the pellets when you apply and come back the next day to sweep the green alfalfa worms into the sod. When the St Aug starts sending out runners, fertilize only over the runners. You are trying to favor the grass and cull out the weeds. Be sure the runners get some water when you are watering the sod pieces. When watering mature grass the idea is to water deeply but infrequently. Deeply means a full inch all at one time. Infrequently means to let the soil surface dry out completely before watering again. This time of year (warming temps into the 70s) that might be every 3 weeks. As much as you can, keep the water off the rest of the yard. When temps warm into the 80s, move to watering every 2 weeks. With temps in the 90s, water every week. Always water the full inch when you water. When the grass is nearly at full coverage you will be watering with a sprinkler. Test your sprinkler by using tuna or cat food cans on the yard. Turn on the sprinkler and time how long it takes to fill up the cans. That is one inch of water. Mulch mow the yard at your mower's lowest setting to kill out the weeds. HOWEVER, mulch mow the St Augustine at the highest setting. Eventually you will be mowing the entire lawn at the highest setting. When the drought comes, continue to mow the weeds but stop mowing the St Augustine. It can grow up to 32 inches high (I don't recommend it), but if yours gets to 6 or 9 inches it will be perfectly fine. Taller grass needs less water. Those short weeds might die with the heat, drought, and mowing stress. I would not kill out the weeds, yet, until you are sure you have the St Augustine established. St Aug will choke out the grassy weeds. Horse herb is one nemesis that might not go away easily, but keeping the St Aug tall will really help. At least with these weeds you have something green. Well kept weeds can look like a lawn for a long time. If the gravel is deep enough you could scoop it out, then do that.

While bermuda can be beautiful, it is a hassle to keep it looking nice. It is one of the few grasses that should be mowed at the mower's lowest setting. Partially due to that, it should be mowed twice a week during the summer to keep from scalping it every week. Bermuda also needs as much water as all the other lawns if you want it to be green. The idea that it needs less water depends on your tolerance for brown grass. When bermuda gets very dry it becomes dormant and turns brown. When St Augustine dries out completely, it dies. Thus you have to water St Aug to keep it alive but you could stop watering bermuda altogether and it would remain alive but brown. Bermuda also needs monthly doses of high nitrogen fertilizer to stay green. This is to say that you can have a bermuda lawn but if you are not willing to maintain it, it is going to look raggedy. It can also thin out and become a haven for weeds. Back in the 50s, before the modern herbicides became inexpensive, when you bought grass seed you got a mixture of a fescue, Kentucky bluegrass, rye, and even clover. The idea was that one of the grasses would dominate in almost any soil and you could have a green lawn with multiple species of plants. That approach is one you might consider. You are in the transition zone meaning that you would be able to grow almost any grass.

Image is too small. However you can apply a per-emergent herbicide such as XL or Amaze mid-Feb., mid-May and mid- September to prevent them germinating in the first place. Here is a link that might be useful: XL

The newspaper, or cardboard, will be digested by the soil bacteria but how long that does take depends on how healthy to soil is and how thick the paper is. In my garden 6 to 8 pages of a newspaper, covered with a mulch, will be digested in 6 months, but other people with soil that has a less active Soil Food Web find the same amount of paper takes over a year to be digested. The major advantage of newspaper, or cardboard, is that it will keep any plant it covers from getting the light that plant needs to grow and therefore that plant will die, but organic matter to the soil.