Welcome to Texas. We will answer your primary question and then introduce you to our website and Native Plant Database. First, we must tell you that the Lady Bird Johnson Wildflower Center and Mr. Smarty Plants recommends only plants native not only to North America but to the areas in which those plants grow naturally. This is for conservation reasons, because a plant habituated to an environment will survive much more readily in the same environment in terms of soils, rainfall, temperatures, etc. You are wise to be choosing plants that have low water use, in view of the heat and drought we had last year, and may very well recur in the future.
Our very first recommendation is that you come to our Spring Plant Sale, April 14-15. Everything in our botanical gardens and sold in the Sale is native to Central Texas. There will be members of the Mr. Smarty Plants Team onsite, and staff members and volunteers to help you find what you need, as well as making recommendations.
Hylocereus undatus, (Dragon Fruit) is a succulent native to Central America and the Caribbean, and therefore not considered native. Also, as you will learn when you follow the plant link, it is a grafted plant, which also does not fall into our definition of "native." The article we have linked you to is very good, with lots of information, and should answer all your questions. We see no reason why it should not grow in a bed prepared for good drainage, with sand or decomposed granite, or both, mixed into the soil.
From eartheasy, here is an excellent article on Xeriscape.
Now, to save ourselves time and work (always an objective) we are going to send you some links, some from our website and some we found online on gardening in Central Texas. Be sure to explore our Native Plant Database.
We will give you a tutorial in using the resources of the Lady Bird Johnson Wildflower Center to help you design your own. Before we do that, allow us to offer our philosophy of gardening. You are not decorating a house. You are not gardening to impress. Plants are not furniture, and none of them look good year round. Think of your property as your environment. Are you economizing on water, a very scarce resource in Texas? Are you using plants native to Central Texas, which impose less of a burden on resources? Are you able to care properly for the plants you have, pulling out the weeds, keeping areas clean, hand watering, if necessary?
These are all questions you need to ask yourself, and then start making your own landscape plan. And, remember, "garden" is a verb. There is real work involved, no matter what you do, and maintenance is forever, so don't get carried away and too complicated. A messy, overgrown yard is unattractive, no matter how much thought and money and water have gone into it.
We have several How-To Articles as well as Step-by-Step instructions, and we hope you will read them as you come to problems related to the subject matter. Please begin with How-To Articles A Guide to Native Plant Gardening and Caring for Your New Native Plants.
1. Begin with what you already have. No doubt you have something, whether it's what you like or not, but trying to totally replace an entire garden in one fell swoop is not only very chaotic, but expensive..
2. Now for the basics, make a map (not necessarily scale) of your area, with buildings, existing trees, sidewalk, driveway sketched in. Watch the amount of sun each part gets for several days, because that is a significant factor in plant selection. Every plant in our Native Plant Database will tell you what the light and water needs of that plant are. You need to include shade from structures, existing plants, etc. We consider "sun" to be 6 or more hours of sunlight a day, "part shade" 2 to 6 hours of sun, and "shade" 2 hours or less.
2. Determine what areas you will be able to water, either with sprinkler system or hand watering. Although you are now out of drought conditions, weather in Texas never stops surprising us-be prepared for the worst and hope for the best.
3. Start with the big stuff first, and plan on trees or large shrubs you want, moving on next to the lawn and blooming plants. Using your sun/shade map, make selections from our Special Collections, Plants for the Edwards Plateau of Texas. There are other plants from nearby areas that will work here, too, but that is a good starting place.
As you have already discovered, selection of succulents is a good choice for a xeriscape, but there are many other plants well adapted to a low water use, semi-desert environment. Be sure and check the water use of any plant you are considering. When you shop for plants, write down the scientific name of the plant (as you did on the Dragon Fruit) and go home and research the plant. Start with our Native Plant Database; if it's not there, it is probably not native, so go search on the Internet. Remember, the whole point of using natives is that they can and do survive here.