They've already begun. "Neil. My St. Augustine is really thin. I want to plant new sod. When can I do it? Where should I buy it?"The questions go on and on. I just want to throw up my hands and say, "Stop! Answer me a couple of questions before you go any further."My first question, whenever anyone says their St. Augustine is failing, is: How much sunlight does the dying grass receive on a midsummer's day? That's because a lot of people have the mistaken idea that St. Augustine requires shade to survive. Only when I remind them that not one of Texas' many big sod farms has one moment of shade do they realize that their thinking might be off. St. Augustine grows best in full sun. Granted, it's more tolerant of shade than bermuda and all of our other lawn grasses, but even St. Augustine needs a good bit of sun. It will hold its own with four to six hours of direct sun, but it needs six to eight hours daily if you expect it to grow and spread.That's more sun than a lot of folks realize. In fact, they'll stand there and say, "Well, that just can't be it. I know it gets enough sunlight." And, that's when I suggest that they look one more time. If the thinning turf is most pronounced up near the trunk, that's where the shade is the heaviest, and that's a deal-cinching clue."Have you already tried resodding that area some time earlier?" They'll reply, "Well, yes I did. Last year, in fact. But, I think I watered it too much (or too little), because it all died. It started dying almost immediately." They admit that they thought they were watering properly. They realize that watering properly probably wasn't the cause of their failure, and they'll quickly drift over to, "I'll just get my trees trimmed for more light." (I've heard this commentary pattern dozens of times.)That pruning and thinning may work for a few months, but the trees are genetically programmed to attain certain sizes. They're just going to regrow and block the sunlight again. In the meantime, their shape and form will be ruined, probably forever. All that money spent. All that frustration. Mangled trees, yet still no grass. Sad, how stubborn we humans can be.Worse yet, people say maybe it's bad soil, and they decide to bring in new topsoil. They end up with mud and nutsedge in the process -- and the grass doesn't grow any better. This is not about having bad soil. Remember the topic: It's all about sunlight.I've actually gone down this path, too. We've lived in our house for 37 years. It was right on the edge of a creek-side pecan forest when we built it. I planted bermuda when our house was new, and our sons and I played ball on our lawn for several years. I converted over to St. Augustine, not so much because the bermuda was failing in the shade, but because I was struggling with allergies every time I mowed. My St. Augustine prospered for 15 or 18 years but, as it grew thinner and thinner, I expanded my beds and added more shrubs and more groundcover, and just in the past couple of weeks, I removed the last vestiges of turfgrass. We live in the country, and I still have a meadow between our house and the county road, but as of March 2013, I'm lawn-free into the future.I love turfgrass, and it's a good investment in our environment. It cools its surroundings, and it's important as a place of recreation. However, when it becomes impossible to grow grass in the shade, you have to figure out alternatives. I discovered many years ago that shade isn't a challenge. It's an opportunity. It's a chance for you to try new plants and new designs.There are many fine groundcovers that will grow in total shade. Mondograss (also called "monkeygrass") is my go-to plant. It's easy to blow or rake leaves and other debris out of its fine-textured blades. I use purple wintercreeper euonymus and Asian jasmine as well, but both produce runners, and it can be a little more difficult to get pecan and oak leaves out of them in the fall. I have significant beds of liriope, wood ferns and aspidistra, and I have smaller plantings of dwarf mondograss, ajuga and English ivy. So, finding a trailing replacement for turfgrass isn't as difficult as one might imagine.The best shrubs in the shade are primarily hollies. In order of increasing size, I've used dwarf yaupon, Carissa, dwarf Chinese and dwarf Burford hollies in large numbers. I also have Berries Jubilee and Dazzler hollies, but those are sadly no longer sold. Stepping up to shrubs that grow to 5 to 8 feet tall, I have leatherleaf mahonia, Gold Dust aucuba, oakleaf hydrangea and, in protected sites, I've grown fatsia and cleyera. Hollies in that 5- to 8-feet range include Needlepoint (Willowleaf), Mary Nell, Oakleaf (Oakland), Robin and Cardinal. Tree-form yaupons, Nellie R. Stevens and Warren's Red possumhaw hollies grow to 10 to 20 feet tall. Japanese maples, dogwoods and rusty blackhaw viburnums are outstanding larger plants for the shade garden.Note: While this information addresses specifically St. Augustine with issues of excess shade, Take All Root Rot, gray leaf spot, chinch bugs and brown patch can attack St. Augustine in sun or shade at various times of the year. We'll have more on them as the season progresses.Neil Sperry publishes "Gardens" magazine and hosts "Texas Gardening" from 8 to 11 a.m. Sundays on WBAP AM/FM. Reach him during those hours at 800-288-9227 or 214-787-1820.