Coming back year after year, perennials are the backbone of many gardens. In general, perennial plants are divided into two categories. Herbaceous perennials are those flowers that die back after blooming to return in the next growing season. Evergreen perennials retain their leaves year around. Low-growing or short perennial flowers are ideal for the front of flower beds, along walkways or in rock gardens. Trim back spent flowers to encourage these perennials to continue too bloom all summer long.
Dianthus (Dianthus) is a low-growing perennial that grows in United States department of Agriculture hardiness zones 3 through 11. The flowers bloom throughout the summer and into fall, lasting until the first frost, in shades of pink, white, lavender and salmon. Each petal of these flowers is fringed and resembles a carnation. Dianthus grows up to 12 inches tall and makes an ideal edging plant along a flower border or path where the flowers can be viewed. This plant grows in full or partial sun and well-drained soil, according to the University of Florida IFAS Extension.
Often used as a ground cover, Carpathian bellflower (Campanula carpatica) produces almost flat, five-petaled flowers throughout the summer months and into fall in USDA hardiness zones 3 through 11. These flowers bloom above heart-shaped green leaves and reach only 8 inches tall, according to the University of Illinois Extension. Carpathian bellflower grows in full sun but prefers partial sun in warmer climates. Flowers are either bluish-purple or white and ideal for rock gardens, containers or the edges of flower beds. This herbaceous perennial is slightly drought-tolerant and isn't picky about soil conditions, making it a low maintenance addition to your garden.
Heat and drought tolerant, verbena plants are an excellent choice for xeriscaped gardens, or those climates with hot, dry summers. Verbena (Verbena) typically grows 12 inches high but spreads between 2 and 5 feet wide according to Clemson University. Blooming in shades of purple, white and red, these plants are covered in flowers from early spring until the first frost. Verbenas thrive in full sun and well-drained soil. Overly-moist soil and poor circulation can lead to the growth of fungus and should be avoided.
Alpine Rock Thyme
Thriving in full sun, alpine rock thyme (Acinos alpines) reaches a height of only 6 inches tall and spreads to 12 inches wide, eventually creating a ground cover. The tiny green leaves complement the small pink to purple flowers which bloom at the ends of each plant stem throughout the summer months. These flowers attract bees and butterflies to the garden. Alpine rock thyme is drought resistant and semi-evergreen, meaning it remains green throughout the winter in warmer climates. Alpine rock thyme grows throughout USDA hardiness zone 4 through 9.