The genus Calibrachoa was first recognized as being distinct from the genus Petunia in 1989, based in part on differences in chromosome numbers. Now, some two dozen species have been placed in the genus, many of which were formerly classified in the genus Petunia. The first commercial hybrids and cultivars of Calibrachoa were introduced to the gardening world in the 1990s. Two competing breeders have introduced hybrids under the brand names Million Bells® and Lirica Showers®, respectively. There is no standard, widely accepted common name for the Calibrachoa hybrids yet, but Million Bells® looks like it may win out, even though it is a registered trademark name. (Kleenex®, anyone?) We at Floridata will stick with Calibrachoa hybrids as the common name for now. (We don’t have to keep typing that little circled R.) There are several named cultivars in the Million Bells® line, differing mainly in flower color, including various shades of violet, blue, red, pink, yellow, orange, bronze, and white. The Lirica Showers® line of hybrids apparently has fewer offerings so far.
The Calibrachoa hybrids have neat, compact foliage 6-9 inches (15-22 cm) tall and spreading to 20 in (50 cm) or so across. They have a finer texture than the true petunias. The leaves of the Calibrachoa hybrids are fleshy, thick and sticky. The flowers are on trailing stems 6-20 in (15-50 cm) long, and look like little petunias with their five spreading, vividly colored lobes and yellow throats. The flowers are about an inch (2.5 cm) in length, and carried in profusion throughout the season. The Calibrachoa hybrids do not normally produce fruits and seeds, and the flowers merely drop off after blooming.
Wild Calibrachoa species (there are a couple dozen) occur in rocky, seashore habitats along the Atlantic Coast in South America, especially Brazil, Argentina and Uruguay. The Million Bells® line of hybrids was developed in Japan by the huge Suntory Ltd. conglomerate, which made its first million brewing beer.
The Calibrachoa hybrids are among the easiest container plants to grow. Use regular, well drained potting soil that is close to neutral in pH, and fertilize every couple weeks. Light: Position Calibrachoa hybrids in full sun to part sun. Moisture: The Calibrachoa hybrids are surprisingly drought tolerant but should have regular watering for best performance. However, do allow the soil to dry between waterings. Hardiness: USDA Zones 9 - 11. The wild Calibrachoa species from South America are perennials with USDA hardiness zone tolerances of 9-11. However the vegetatively propagated hybrids are quite hardy, to 15 °F (-9 °C), and often persist and bloom until a true hard freeze. Not only that, they tolerate high temperatures, too.
Propagation: The Calibrachoa hybrids produce few if any seeds and the plants are propagated from cuttings. Of course, it is unlawful to propagate registered cultivars without permission from the copyright owner.
The Calibrachoa hybrids are perfect for containers that hang in hot sunny situations.
The Calibrachoa hybrids make great bedding plants, but are a little expensive for that since they are typically sold in small pots rather than flats. Instead, these little petunias usually are grown in containers and are especially effective in hanging baskets and window boxes. This is a fast growing, vigorous annual that is remarkably tolerant of heat and full sun. The foliage has a compact bushy habit and the flowers are borne on long trailing stems that cascade over the container. Unlike true petunias which eventually wind up with lots of seeds and stop blooming, the Calibrachoa hybrids don’t produce seeds, and therefore you do not need to pinch off spent flowers. Blooming will continue until the first freeze. You can, however, pinch off long trailing stems to encourage bushier plants.
If you haven’t already been seeing these beautiful new introductions at your local nurseries, you will. And, expect many more variations to come.