Calibrachoa (Calibrachoa spp.) is a fast-growing, tender perennial commonly grown as an annual in the United States. Hardy in U.S. Department of Agriculture plant hardiness zones 9 through 11, its trailing branches work well in hanging baskets, window boxes and garden borders. Commonly known as million bells due to its prolific, colorful blooms, this heat-tolerant plant comes in a wide range of colors. The petunia-like flowers attract hummingbirds.
Plant million bells in a moist, fertile, well-drained soil. A soil with slightly acidic pH between 5.5 and 6.0 with plentiful organic matter is ideal. Place the plant at the same deepness it was growing at before.
Fertilize container plants weekly with a complete, balanced fertilizer where all three numbers are the same. For example, mix 1 tablespoon of 10-20-10 fertilizer with 1 gallon of water and apply. Allow the fertilizer to run through the bottom of the pot to keep soluble salts from building up in the soil.
Fertilize garden-grown million bells by broadcasting a controlled-release, 14-14-14 fertilizer over the soil once every four months during the growing season. Water the area well after applying fertilizer.
Water million bells when the top of the soil feels dry. The plant is drought-tolerant, but containers dry out quickly. Keep the soil moist, but never soggy; too much water leads to root rot. Make sure your pot has good drainage and water flows through freely.
Place your million bells in full sun for the most blooms, but early afternoon shade is appreciated in hot locations. Million bells bloom from May through late fall. Shade does reduce blooming, so strive for very little shade.
Pinch long, leggy branches to produce a bushier plant, if desired. Use your thumb and forefinger to pinch the stems directly above a set of leaves to promote branching. Note that pinching delays blooms for up to two weeks.