For vibrant color from spring to frost, plant Calibrachoa. In hanging baskets or pots, they trail over the sides and act as a “spiller” in combination plantings.
Calibrachoas are native to South America, along with petunias. They were introduced to the US market as Million Bells® in the 1990s and have grown in popularity over the years. The majority are produced vegetatively and have been trademarked by breeding companies. They are available in different plant sizes and habits, including compact, medium, and vigorous growers.
They are available in many flower types and colors. There are both single and double-flower varieties. Single flowers can have contrasting “eyes” and star or veined patterns; some change flower color as they age. The flowers are self-cleaning and do not require deadheading.
Calibrachoas grow best in pots and hanging baskets. Be sure to plant them in well-drained potting soil. Add a slow-release fertilizer, such as Osmocote®, when planting. If you prefer to use a liquid fertilizer, feed every 2 to 3 weeks throughout the growing season. They prefer full sun to part shade. In the dog days of summer, they appreciate some afternoon shade.
Hanging baskets of Calibrachoa are readily available at most nurseries. To make your own, use a hanging basket 12 to 14 inches in diameter with 3 to 4 plants per basket. Try color combinations based on the color wheel. Analogous colors (next to one another) on the color wheel, like red, orange, and yellow, match very well. For contrast, plant complementary colors (opposite one another on the color wheel) like magenta, gold, and blue. Use Calibrachoas in mixed containers with verbena, petunia, bidens, fan flower, lantana, and many more.
When planting them in the garden, choose a site with very good drainage, such as a raised bed. Avoid planting in heavy clay soils.
Calibrachoa is considered an annual in most of South Carolina. In the Upstate, I have occasionally had them winter over when the winter is mild.
For more information, see HGIC 1152, Growing Annuals.