Just want to clear up an inaccuracy here: "He urged me NOT to pull any more even in flower beds because PULLING THEM SPREADS THE NUTSEDGE!! He said the seeds are in the "nut" at the base of the root system, so when you rupture/disturb the nut by pulling, all those seeds spread all over and get in the lawn too. I can't believe I've been inadvertently spreading it!!!" Seeds of nutsedge, Cyperus rotundus or esculentus, are NOT contained in the nutlets! They will be located in the flowerheads that form at the top of the plant. But they are not the problem as purple nutsedge seldom produces any seed and yellow nutsedge seeds have minimal germination viability. An established plant will produce multiple nutlets as well as a rhizomatous root system. Sometimes as many as a hundred or more. That's how the sedge multiples and why pulling is so ineffectual - unless the soil is very loose and friable, it is almost impossible to get all the roots and all the nutlets out and any single remaining tuber (nutlets) will regenerate as a new plant. So disturbing or rupturing the nutlet does not spread any seeds. But it is easy to spread the tubers while in the process of physical removal. Any tilling, plowing or even just routine cultivation of a planting bed can spread the tubers. Any tuber left in place will rapidly form a new plant. Control is not a once and done. It will generally take repeated applications of a dedicated sedge killer or a broad spectrum herbicide. Same with manual removal of the topgrowth/starving the plant via denial of photosynthesis. Most sources state a 2-3 year period of focused control methods before a 90% elimination of any remaining tubers.

I was thinking the same thing. You can't get rid of bermudagrass without killing the St. Augustine. The good news is the St. Augustine stolons grow a half inch a day in the summer. So killing the yard and starting over wouldn't take long. You say the front yard is nearly perfect so in the perfect areas use some of your yard as a nursery and plug the back. The front will recover quickly and the back will soon be looking as good as the front. The key is using the top labeled amount which could range from 3 to 5 ounces per gallon. Then to use it as soon as you can then in about 2 weeks. You should have pretty much wiped out the back lawn. I would then cut the grass as low as possible then plug all you can. Keep it well moist and then wait. I would think by the end of next year you should have a solid back yard. Good luck.

The problem with repellents is twofold: one, they all wear out after a while and need to be changed. Not refreshed, but changed - use a different repellent on a rotating schedule. Second, in my experience city animals are more used to a variety of scents and aren't as afraid of repellents. A fence is really the only certain thing if traps aren't working. Have you tried super stinky bar soap as a repellent? It can only be used every so often because of the effects on the soil, but ime was effective. I shaved it - literally shredded it - and spread it around. Lasted longer than the other repellents I was using at the time. The one thing I can think of that you haven't mentioned is used cat litter, or letting a cat roam your yard. In my experience that is the only thing that keeps them away from my tender young bean plants. If you don't have a cat sometimes the shelters will let you have a bucket of used litter. Be careful not to use the clumping type, it is a nightmare on your soil or grass; there are lots of biodegradable types of litter that will even serve as fertilizer eventually. And you should not apply it to soil around any food crops. (mine is on the grass surrounding the raised bed, not in the bed itself.) On a side note, I planted my front yard with extra clover in an attempt to keep them away from my back yard, on the theory that they like to eat the clover and will stay busy with that. I can't tell you if it worked because the clover hasn't sprouted yet.

Lay it on the ground; put a flattened cardboard box on top of it; pound it with a hammer or small sledge. If you want to get fancy, put a piece of visqueen under it to aid in ckeanup. Even though the cardboard should protect you, it's alweays a good idea to wear safety goggles.