Black-eyed Susan takes root in hardiness zones 3 to 9. The black or dark brown center combines with long, yellow petals to create a flower that appears to be a cross between a daisy and sunflower. The North Carolina State University Cooperative Extension hails the black-eyed Susan as one of the most popular, toughest and beautiful perennials grown today.
The carpathian harebell is a low maintenance flower that can sport either blue or white petals, depending on the strain. The University of Illinois Extension says that the carpathian harebell is a partial sun flower ideal for rock gardens although the plant may be short lived in hotter climates.
Shasta daisies grow from approximately 1 to 3 feet in height in hardiness zones 4 to 9. Shasta daisies have a distinct appearance, with white petals surrounding a vibrant yellow center. Shasta daisies prefer well-drained soil and full sun exposure.
Aster flowers can have violet, pink, blue or white petals, depending on the variety. Found in zones 4 to 8, the North Carolina State University Cooperative Extension reports that all Aster strains have yellow centers and daisy-like flowers.
One of the hardier perennials found in the U.S., the bearded iris thrives in hardiness zone 3 to 10. Long, colorful petals hanging from a central bloom are characteristic of the bearded iris, which prefers full sunlight.