Most landscape flowering plants are divided into two categories - Annuals and Perennials.
There is a place in every landscape for both of these plant categories.
Because we are in Zone 8, if you purchase a plant that is considered a perennial in Zone 9 or greater (warmer), you can plant it and it will grow, but you will need to treat it as an annual. Most plants in these warmer zones are considered tropical and won't handle our winter temps. So be aware of that and read those plant tags!
Reliable Annuals for Seasonal Color - a list of annuals that perform well in our area.
Perennials for Texas Landscapes - Dr. Bill Welch is editor of The Southern Gardenweb site within Aggie Horticulture. He is also a contributing editor for the Horticulture Update newsletter.
Perennial Garden Color - information on some classic perennial landscape styles.
Cutflower Gardening - includes a nice list of annuals and perennials that you can cut and bring inside to enjoy.
Tips on Dividing Perennials To increase your stock of perennials, divide spring and summer bloomers during the fall and winter.
Outstanding Perennials for Texas - List of perennials that perform well in Texas - those designated for Region 4 will do well in Collin County. Plants designated with a "7" from this list will do well all over Texas.
Texas SmartScape® database - Under the Plant Type field, select 'Perennials' and click the Search for Plants button. (Or chose additional fields to drill down your search, such as plant shape, bloom color, and more.)
Cornell Herbaceous Perennials was created by Texas A&M University professor and Cornell alumnus Allison Meyer. It is searchable via scientific name, common name, and photographic indices as well as through a search page in which visitors may enter more detailed criteria such as plant names, family, flower color, plant height and growth habit, foliage texture, propagation methods, hardiness zone, season of bloom, and water and light requirements. Note: Check the hardiness zone and PH preferences to make sure that the plants you choose from this list will perform well here in Collin County. Cornell University is in Zone 5 and Collin County is considered Zone 8, so some of these plants may not perform well in Texas.