Perennials in Colorado

Spring Bloomers

• For colorful blooms early in the season, plant perennials that flower from March through May. Selections for Colorado include basket of gold (Aurinia saxatilis), a 12-inch-tall perennial that blooms with yellow flowers atop gray-green foliage. Hardy in U.S. Department of Agriculture plant hardiness zones 3 to 7, this spreading perennial grows well in sunny, well-draining sites or rock gardens. The columbine (Aquilegia canadensis) also blooms in spring. Reaching heights of 1 to 2 feet, this North American native produces hanging red and yellow blossoms. It's hardy in USDA zones 3 to 8 and prefers moist, partially shaded sites. The blue, purple or cream-colored Rocky Mountain columbine (Aquilegia saximontana), the state flower, grows in zones 4 to 8.

Summer Bloomers

• For blooms from June through August, plant hollyhocks (Alcea rosea). These upright perennials add vertical interest to the garden, growing up to 5 feet tall and blooming with showy pink, purple, white and yellow flowers through the summer. Hardy in USDA zones 5 to 9, hollyhocks grow best in sunny, well-draining sites. Another summer bloomer, the Carpathian harebell (Campanula carpatica), adds white, purple and blue tones to your Colorado landscape. This perennial grows in USDA zones 3 to 8 and reaches heights of less than 3 feet.

Fall Bloomers

• For late season color, plant perennials that bloom from August until frost, such as the sneezeweed (Helenium autumnale), a 2- to 5-foot-tall species that produces yellow, red and orange blossoms. Hardy in USDA zones 3 to 8, the sneezeweed prefers moist, sunny sites and comes in a range of cultivars. It can be invasive in some areas, so keep an eye on its growth. The "Autumn Joy" sedum (Sedum "Autumn Joy") also offers fall color. It blooms in late summer with pale pink buds that mature to a coppery red. It's hardy in USDA zones 3 to 10 and thrives in sunny exposures and well-draining soil. Asters (Aster spp.) also bloom in fall; these versatile perennials grow from 1 to 4 feet tall and flower in shades of pink, white and blue. They're hardy in USDA zones 5 to 8, where they grow best in sun and well-draining soil.

Long Bloomers

• Some perennials produce flowers for a few months at a time, such as the catmint (Nepeta spp.). These 1- to 3-foot-tall perennials bloom from May through October with white, blue and purple blossoms. They're hardy in USDA zones 3 to 8 and prefer sunny, well-draining sites. Some catmint species are known to be invasive, but noninvasive varieties, such as Little Trudy (Nepeta x "Psfike" P.P. #18904), are available. The tiny Corsican violet (Scabiosa caucasica) produces its blue-purple flowers from April through October. Growing from 6 to 8 inches tall, these perennials add low-growing color and texture to the garden. They're hardy in USDA zones 4 to 9 and grow in full sun or partial shade.