Calibrachoa is a small genus of abundantly flowering plants that are often planted in gardens for decorative purposes. It has numerous flowers that look like tiny petunias, and common names such as mini petunia and million bells referring to the flowers. Calibrachoa originated in South America, and is closely related to standard petunias. It has a tendency to grow extremely quickly, and will remain covered with flowers with under the right conditions.
Calibrachoa is usually a low growing plant that typically grows to a height of about 4 to 10 inches (10 to 25 cm) tall and can spread out as far as 24 inches (61 cm) wide. The light green stems are fleshy and branch out multiple times. The leaves are bright green with an oval shape and a fuzzy texture. The flowers are petite with a narrow, bell-like shape that flares out at the end into open petals. The flowers come in a wide variety of colors including red, pink, purple and white.
Like petunias, the genus Calibrachoa is classified as belonging to the Solanaceae family of plants, which also includes tomatoes and deadly nightshade. It is closely related to petunias and was formerly considered part of the genus Petunia. Genetic differences in the number of chromosomes between the two plants revealed through scientific study resulted in it being moved to its own genus.
In its native area of South America, Calibrachoa grows as an evergreen perennial. It can't survive winter weather so it is cultivated as an annual for use in gardens in the rest of the world. It prefers a warm tropical climate with plenty of heat and humidity, but it is able to thrive during the warm seasons in areas with temperate climates as well.
In gardens, Calibrachoa is used in flower beds, borders, or containers. Many gardeners prefer it in containers, where it tends to spill over the sides in an attractive way. Hanging baskets, where it has a trailing effect, are also popular. This plant needs full sun to part shade, but it produces more flowers in full sun. It should be watered at least twice a week, and more often if the weather is very hot or dry. The soil should be moist with good drainage so it doesn't become saturated.
To encourage lots of flowers old blooms can be pinched off, but this isn't required. Calibrachoa doesn't produce many seeds, so it's easier to propagate using cuttings from existing plants. However, many of the varieties are patented, and it's illegal for gardeners to propagate them.