Million Bells (Calibrachoa syn Petunia) are short lived perennials which are often planted as summer annuals in South Africa – growing and flowering at an amazing rate! They bloom abundantly all spring and summer, until the first frosts, and in warm frost-free regions can flower all year round.
It is a relatively recent newcomer to the garden scene, having only been around since the early 1990s – and that’s not long in plant years! Plant breeders have been hard at work on this little marvel, and today Calibrachoa hybrids are available to gardeners in many amazing shades of cherry, red, rose, pink, violet, blue, yellow, lemon, terracotta and white.
These summer sizzlers are closely related to petunias and found across much the same region of South America as petunias, from southern Brazil across to Peru and Chile, inhabiting scrub and open grassland. And, although they look like a miniature petunia, and were previously included in Petunia, scientists now say they are not quite petunias, because, amongst other things, petunias have 14 chromosomes and calibrachoa has 18.
In sunny garden beds they generally remain below 15cm in height with a spread of +-30 to 60cm, making them good partners for other sun loving annuals and perennials in the garden. In pots they will cascade up to 60cm or more, and their sprawling habit adds a beautiful cascading accent for all kinds of containers and hanging baskets. Whether you let them trail down banks, over low walls or tall pots, or simply use them in massed plantings for a quick, colourful groundcover, Million Bells is sure to impress.
Million Bells are easy to grow as long as you meet their growth requirements. They flower best in full sun, although in very hot regions some midday shade may be welcome. Although they will grow in most garden soils which have perfect drainage, Million Bells thrive in slightly acidic soils, so if your soil is alkaline, add acid compost to the planting beds. If you’re planting into containers, use a top quality, free-draining potting mixture.
They also require good air movement around their leaves, so place them where there is a slight breeze. And, although the plant is water-wise, this does not mean that it does not need watering! Water as needed in hot weather, but allow the soil to partially dry out before watering again. Overwatering is the leading cause of plant failure, causing black root rot.
The plants are self-cleaning, meaning that they shed their spent flowers naturally and replace them with new ones, but an occasional light pruning and a bit of dead-heading won’t harm them.
Because these plants bloom continuously, those growing in garden beds will benefit from a monthly feeding, using a fertiliser for flowering plants. For potted plants, feed every second week with a liquid fertiliser, which is easiest to apply without burning, and you can also mix slow release fertiliser into the soil when planting.
Calibrachoa can be propagated easily from cuttings but propagation is prohibited by plant breeder rights in many countries. Although the plants produce few seeds, the seed is also easily propagated.
If grown correctly, Calibrachoa is generally very healthy. However, too much moisture and shade will make it susceptible to root rot, crown rot, and collar rot. To help prevent this, water early in the day and provide plenty of sunshine to keep the foliage and the flowers dry. This is especially important in humid areas.
Calibrachoa is less sensitive to pests than petunias, but may attract a few pesky bugs like thrips, aphids, and whiteflies. These can be treated with organic insecticidal soap sprays.