Texas Rock Rose: (Pavonia lasiopetala): Small shrubb. 3ft*3ft. In the mornig these small shrubs/woody perennails and covered in 1in wide pink hibiscus like blooms. THe flowers close in the afternoon. TX native that's EXTREMELY drought tolerant. Z8 and up. Short lived, but self seeds easily.>
Plumbago (Plumbago auriculata): White or blue varieties. Small shrub. Can be grown as a tender perennial in Z8, fully hardy Z9 and up, annual elswhere. Very Drought tolerant, doesn't miss abeat in the heat. Blooms on new wood. In z8 it will die back to the ground.
Mexican Petunias(Ruellia brittoniana): 2-3ft tall and wide evergreen perennial. Loves the heat, very drounght tolerant in ground, in areas with enough moisture it can be a bit invasive(or so I have read).That's not a problem for me (annual rainfall about 25in a year). Wilts frequently without plenty of water in containers. Comes in purple, pink and white. Also comes in a dwarf variety that's only 8-10 in tall and white. Perfect border plant Hardy Z8-10, marginal with protection in Z7
Passion Flower: Distinctive Flowers and floiage. Some varieties are evergreen and bloom year round. Excellent substitute for Clematis. My favorite variety is Lavender Lady. A sterile variety. Best blooms are in Sept-December, but will bloom throughout the year. Flowers are about 5 in wide. No pest or desease issues. Takes the heat EXTREMELY well (not all passion wines likes heat) and is VERY drought tolerant.
Datura/Moonflower Bush/Jimsonweed: *Poisonus* 2-ft tall and wide. Enormeous white flowers open at dusk, and dies in the late morning. Very heat and drought tolerant. Owerwinters for me in Z9. Probably an annual most elsewhere. A good similar plant is Angels Trumpets. Datura, flowers pint up, Angel T. flowers point down. Angel Trumpets also comes in different colors beside white. Pale yellow, peach, pink and purple. Double flowers also available.
Purple Mist Flower. Easy going perennial. Partial shade, sperads, but is easily confined. I like to let it ramble around other plants. Can withstand heat and drought. Colors range from bluish~purple~white
Salvia.... Salvias are the BACKBONE of my garden. From evergreen shrubby perennials to fast growing annuals. I personally divide Salvias in 2 Groups. The Blues, and the Red-Pink-White
Salvia Greggii. Shrubby evergreen perennial. Should be chopped back hard in early spring, and cut back by 1/3 3 times a year to prevent them from becoming woody and leggy, and to encourage a new flush of blooms. Tolerates heat and drought. Comes in Whites, Pinks, Corals and Reds. 2-4ft tall and wide.
Tropical Sage: Tender perennial Z9, Red-White-Pink. Cut back spent blooms to encourage bushiness and flowers. Self seeds easily, and grows EXTREMELY fast.
Mealy Cup Sage 12in*12in. Blue-silvery/blue-white Great little reliable, don't really have to give it much attention. EXCEPT. Humid weather encourages POWDERY Mildew. Easy to take care of preventative. Blooms sun-shade.
Indigo Spires: Purple flowers 5ft tall*3ft wide. A "dwarf" variety is also out that gets to be 3ft*3ft. Cut back by 1/3 after every flush of flowers to encourage bushiness and flowers. Very drought tolerant. Does in my experience not self seed.
I have many other salvias...I think salvias will work for any garden any style, depending on how they are used.