How to Grow Million Bells Flowers

Yellow and Pink Million Bells (Calibrachoa) Flowers

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Million bells is an annual flower that blooms nonstop from spring to frost without the need for deadheading. It is most commonly grown in containers, where it spills gracefully over the sides of the pot or hanging basket but has a dense trailing habit rather than a spindly one. Million bells plants also attract hummingbirds and butterflies to boot. The blooms of million bells are approximately 1 inch across, and many sport veining or colorful throats that contrast with the primary petal color. The foliage is bright green, oval-shaped, and compact.

Your grandmother probably didn’t grow million bells but not because they didn’t exist. Petunias and million bells were exported from South America to Europe in the 1800s and later to North America. Petunias ruled until 1997 when Proven Winners licensed the up-and-coming million bells from its breeder, Sunstory Ltd. Million bells filled a rainproof, hot weather-loving niche that petunias couldn't. 

  • Botanical Name: Calibrachoa (hybrid)
  • Common Name: Million bells, trailing petunia
  • Plant Type: Annual (in most climates)
  • Mature Size: 6 to 10 inches high and 12 to 18 inches wide
  • Sun Exposure: Full sun, part sun
  • Soil Type: Soil-free potting mix or well-drained soil
  • Soil pH: 5.2 to 6.0
  • Bloom Time: Spring to frost
  • Flower Color: Pink, yellow, red, violet, white, blue, magenta, bronze
  • Hardiness Zones: 9, 10, 11 (when grown in ground)
  • Native Area: Hybrid bred from South American native plants

How to Grow Million Bells Flowers

Million bells plants are tender perennials, but most gardeners treat these spring-through-frost bloomers as annuals. Their trailing habit and low-maintenance, prolific blooms make them excellent candidates for containers and hanging baskets. Million bells are also somewhat drought-tolerant, so you can include them in the rock garden, where they will appreciate the sharp drainage conditions. If you use million bells as a ground cover, keep in mind that plants seldom spread more than 2 feet, so plant enough to ensure adequate coverage.

Light

Million bells flowers grow best in full sun. Bright dappled shade or afternoon shade are second-choice placements in the garden but may turn your “million bells” into “hundred bells,” due to a reduction in blooming.

Soil

Fill your planting containers with soil-free potting mix amended with humus or compost. Potting mix will ensure the excellent drainage necessary for plant health, as million bells hate wet feet.

If you are growing the plants in the ground (they're hardy only to zone 9), plant them in rich, well-drained soil with a slightly acidic pH of 5.2 to 6.0. Space the plants to allow for spreading, about 18 inches apart. Cover the soil with organic mulch to keep the root system cool and to stop evaporation.

Water

Keep the plants evenly moist; the soil should not completely dry out. Do a "swing test" daily if you have hanging baskets: Does the basket seem as light as a feather when you give it a push? If so, you must irrigate until water flows through the drainage holes. If you're using pots or similar containers, test the soil for moisture by inserting your finger up to the second knuckle; if the soil at your fingertip feels dry, it's time to water. Add water until it comes out of the container's drainage holes. Test the soil regularly to keep on top of watering needs.

Temperature and Humidity

Million bells thrive in warm and hot weather, but they can become heat-stressed. If you live in a dry climate, you can try misting the plants daily or as needed to revive the foliage, but do not mist in direct sunlight, which can lead to leaf burn.

Fertilizer

Fertilize your million bells every two weeks throughout the growing season with a liquid flower fertilizer, which provides nutrients more quickly than time-release formulas. This is especially important at summer's end when plants appear to be bloomed out. If your million bells have light green or yellowish foliage, this is also a symptom that they need a nutrient boost (or more sunshine). 

Varieties of Million Bells

Million bells is the most well-known hybrid in the Calibrachoa group, all of which are technically hybrids, not native plants. Within this group, there are many different varieties and colors to choose from, including:

  • Kabloom: Seeds available in pink, white, red, yellow, and deep blue
  • Crackling Fire: Dark neon-orange flowers marbled with yellow
  • Tangerine: Cheerful clear-orange flowers with red veining
  • Terra Cotta: Yellow flecked with red
  • Trailing Sky Blue: Bright lavender-blue flowers with green throats
  • Cherry Pink: Hot pink flowers with yellow throats; a hummingbird beacon

Growing From Seeds

The majority of million bells on the market today are hybrid plants that are vegetatively propagated, so you must grow these from plants rather than seed. However, the newer Kabloom series offers gardeners an economical way to grow million bells from seed, with the same self-cleaning habit and prolific blooms of other varieties. The trade-off is a significant waiting period, as it takes about four months from sowing to bloom for these plants. Million bell seeds need light for germination, which takes about two weeks.

Common Pests

Million bells that are planted too early in the spring may fall prey to aphids. To prevent this, plant them outdoors around the same time you plant your tomatoes.

Whether they're grown in containers or the ground, keep your plants from becoming heat stressed, which tempts spider mites. If the weather conditions are dry and dusty, practice cultural control of these pests by misting plants with water daily.

Unlike petunias, million bells don’t suffer from the dreaded tobacco budworm.