Covering the state's largest geographic area, 8a and 8b include Central Texas. The area from El Paso to Dallas-Fort Worth enjoys the benefits of 8a, while 8b covers the area from the Rio Grande through San Antonio and Austin to Nacogdoches and the state's eastern border. Average low temperatures in winter range from 10 to 20 °F. When making a selection of plants, it is important to know the areas in which the plant will grow better.
What that means for the Austin gardener is that it's really hot and it seems to get hotter every year. Monitoring your gardening experiences can show that you can grow plants in slightly colder or warmer areas. It's important that you know your specific growing zone to ensure that the time you spend in your garden is the best chance of success. This system divides the United States and Canada into eleven zones, based on the average minimum temperatures in winter.
If you are in an area where you have a greater number of cold hours and plant one destined for low cold hours, this will cause it to bear fruit prematurely and you will lose your fruits with the next frost. This zone covers a strip that extends from the New Mexico border in western Texas to small sections of the eastern borders of Oklahoma, Arkansas and Louisiana. One way to determine which plants will thrive in Central Texas is to understand the USDA hardiness zones. Knowing your specific area can make the difference between losing plants that are less resistant to winter frosts and preventing them from frying in the extreme heat of the higher areas.
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 your list of favorite gardening products includes plants that aren't resistant in your area, consider planting them in pots that can be brought indoors during extreme winter. You could also expand your plant options a little beyond your area if your property includes areas with microclimates at a different height or with more or less protection from the elements, making temperatures and conditions slightly different within your property or general location. Labeling and plant growth information are sometimes limited to “Texas,” making it difficult to identify which of the many USDA Texas areas are appropriate places for cultivation.
As the second largest state in the United States, the Texas landscape includes four different USDA zones. Once you've identified your area, read magazines, catalogs, and websites and visit nurseries to find out which plant palette will be most suitable nice for your garden.