The sunny faces of coreopsis (Coreopsis spp.), also called tickseed, are native plants that have also been bred for gardens. About 80 species grow wild throughout the Americas. Plant breeders work primarily with North American species to develop new hybrids and varieties every year. Coreopsis are garden favorites because of their easy care, long-lasting blooms, use as cut flowers and wide color range. Although they tolerate many soil types, they need good drainage.
1. Large-Flowered Coreopsis
Large-flower coreopsis (Coreopsis grandiflora) is a perennial Texas wildflower with yellow flowers that grows in U.S. Department of Agriculture plant hardiness zones 4 through 9. It has several cultivars, including "Early Sunrise" with a semi-double flower and single-flowered "Heliot," which has a red blotch at the petal bases. "Sunray" has showy fully double golden-yellow flowers that make long-lasting cut flowers in bloom from spring to late summer, if deadheaded.
2. Thread-Leaf Coreopsis
The finely dissected foliage of thread-leaf coreopsis (Coreopsis verticillata) makes an airy backdrop for single yellow flowers of this native eastern North American wildflower that grows in USDA zones 4 through 9. A number of cultivars and hybrids in many colors are available. "Moonbeam" has lemon yellow flowers on a 15- to 18-inch-tall plant and was awarded the Perennial Plant Association Plant of the Year award in 1992. "Route 66" has 2-inch yellow flowers with a deep burgundy ring around the center eye, and grows 24 to 28 inches tall. "Zagreb" has bright yellow flowers on a bright-green 18-inch-tall plant. Showy hybrids include stop-sign red "Center Stage" and glowing pink "Center Stage."
3. Pink Coreopsis
Pink coreopsis (Coreopsis rosea), another wildflower grows in moister areas and is the exception to the rule that all coreopsis need good drainage. It grows in wet, sandy soils of coastal plains along the East Coast and is hardy in USDA zones 4 through 10. The cultivar "American Dream" has pink flowers above narrow green foliage on a 12- to 18-inch plant. Colorful pink coreopsis hybrids include deep, mahogany-red, single flowers of "Limerock Ruby," growing to 18 inches tall and wide in USDA zones 7 through 9; "Heaven's Gate" with red-centered pink flowers on 18- to 24-inch tall plants in USDA zones 6 through 9; and "Sienna Sunset," with newly opened flowers a burnt sienna color that fades to light orange in USDA zones 5 through 9.
4. Hybrid Series
There are so many impressive hybrid coreopsis each year that it's impossible to keep track. The Big Bang series contains mostly yellow and red flowers; the Punch series goes through warm, fruity colors, such as red, lemon, and mango; the Pie series holds cherry, pineapple and pumpkin colors; the Hardy collection has flowers in red-and-white, red, pale yellow, golden yellow and a folded-petal pinwheel-flowered form. Show-stopping colors of "Desert Coral," "Garnet," "Pink Sapphire," "Citrine" and white-rimmed red petals of "Ruby Frost" compose the Hardy Jewels series. There are yet more, truly a color for every garden design. Most hybrids grow in USDA zones 4 through 9.