Austin belongs to the humid subtropical climate according to the Koppen climate classification. This climate is characterized by long, hot summers and short, mild winters, with warm transient periods in spring and autumn. If you are in an area with a greater number of cold hours and you plant an area destined for low temperatures, fruiting will be premature and you will lose the fruits with the next frost. Be sure to heed suggestions as to how much sun a plant can handle and how much water it will need, and you'll be well on your way to a stunning, climate-friendly garden.
If you choose a fruit tree with high chill hours (such as one that would do well in Dallas with nearly 1000 chill hours) but you live in Austin and may only get 400 to 600 chill hours, you may end up with no fruit at all. Central Texas is a unique region with a particular climate, and it's important to choose plants that are adapted to this climate to create a successful landscape. The geology of Texas is fascinating and, if you haven't done your homework on the geological history of Texas, I encourage you to do it, as it's impressive. Choosing an expensive tree that prefers to have wet feet in a climate where there is very little rainfall can be a financial disaster.
I had a hard time finding a decent cold hour map, so I'll cheat and tell them that those in Austin have between 400 and 600 cold hours, if they're farther north of Austin they're 600 to 800 and farther south, it's between 200 and 400, which is where their citrus fruits will grow best. If you're looking for some ideas for plants that are well suited to your garden, here's a list of common plants used in gardening that will thrive in USDA hardiness zone 8b. What this means for the Austin gardener is that it's really hot and it seems to get hotter every year. Once you have a better idea of the type of climate you live in, you can make better decisions about the type of garden you want to grow and the amount of work ahead of you.
One way to determine which plants will thrive in Central Texas is to understand the USDA hardiness zones.