Calibrachoa, commonly known as Million Bells, is a vibrant flowering plant native to South America but widely cultivated in the USA. Resembling miniature petunias, these plants thrive in hanging baskets, containers, and garden beds. They are prized for their prolific blooms and low-maintenance nature, making them a favorite among gardeners.
Calibrachoa prefers full sun, requiring at least 6-8 hours of direct sunlight daily for optimal blooming. In hotter regions like the southern USA, partial shade during the afternoon can prevent scorching. The plant thrives in USDA hardiness zones 9-11 but is often grown as an annual in cooler climates. Well-draining soil with a slightly acidic to neutral pH (5.5-6.5) is ideal.
Start by selecting a location with adequate sunlight. For container planting, use a high-quality potting mix enriched with organic matter. Space plants 6-12 inches apart to allow for air circulation. If planting in garden beds, amend the soil with compost to improve drainage. Calibrachoa can be propagated from cuttings or purchased as nursery-grown seedlings.
Calibrachoa prefers consistently moist soil but is susceptible to root rot if overwatered. Water deeply when the top inch of soil feels dry, ensuring excess water drains away. In hot climates, daily watering may be necessary, especially for container-grown plants. Avoid wetting the foliage to prevent fungal diseases.
Feed Calibrachoa every 2-3 weeks with a balanced, water-soluble fertilizer (10-10-10 or 20-20-20) to support continuous blooming. Alternatively, use a slow-release fertilizer at planting time. For organic options, compost tea or fish emulsion can be applied monthly. Avoid over-fertilizing, as this can lead to excessive foliage growth at the expense of flowers.
While Calibrachoa is self-cleaning (sheds spent blooms naturally), occasional pruning encourages bushier growth and more flowers. Trim back leggy stems by one-third in mid-summer to rejuvenate the plant. Remove any yellow or diseased foliage promptly to maintain plant health.
Common pests include aphids, spider mites, and whiteflies, which can be controlled with insecticidal soap or neem oil. Fungal diseases like powdery mildew may occur in humid conditions; ensure proper spacing and avoid overhead watering. Root rot can be prevented by using well-draining soil and avoiding waterlogged conditions.
In colder regions, Calibrachoa is typically grown as an annual. However, in zones 9-11, it may survive mild winters. To overwinter, bring potted plants indoors before the first frost and place them in a sunny window. Reduce watering and withhold fertilizer until spring. Cuttings can also be taken in late summer to propagate new plants for the following season.
Popular Calibrachoa cultivars include 'Superbells' (known for vibrant colors), 'MiniFamous' (compact growth), and 'Cabaret' (large blooms). Choose varieties based on your climate and desired color palette, as some are more heat-tolerant than others.
Yellowing leaves may indicate overwatering or nutrient deficiencies. Poor flowering can result from insufficient sunlight or excessive nitrogen. If plants become leggy, increase light exposure and prune regularly. Adjust care practices based on observed symptoms to ensure healthy growth.
