My grandmother's favorite--Lantana is so easy to grow. It attracts butterflies, loves sun and can tolerate drought. Good watering results in a showy and large plant. Freezes to the ground in winter but returns year after year.
Day Lillies and Black Eyed Susan. Trumpet-shape daylilies come in colors such as pink, red and orange that complement classic orange-yellow black-eyed Susans. Both bloom midsummer; black-eyed Susan flowers last until midautumn.
Zinnias, such a sun loving, heat tolerant, hearty flower. Toss some seeds in prepared soil in late spring and watch your garden burst with color in no time. You can grow these in containers as well if your yard space is limited. Makes for a great cut flow