Calibrachoa is a genus of plants in the Solanaceae (nightshade) family. They are weak evergreen short-lived perennials and subshrubs with a sprawling habit, with small petunia-type flowers. They are found across much the same region of South America as petunias, from southern Brazil across to Peru and Chile, inhabiting scrub and open grassland.
Calibrachoa are closely related to Petunia. However on further examination it has been found that there are major differences in chromosomes, corresponding to external differences and fertilization factors that distinguished the two genera. Petchoa is a hybrid genus derived from crossing the genetically similar Calibrachoa and Petunia. 
Calibrachoa is named after Antonio de la Cal y Bracho, a 19th century Mexican botanist and pharmacologist.
Some Calibrachoa are cultivated as ornamental plants, the hybrids C. ×hybrida being popularly known as "Million Bells". The plants can tolerate light frost and thrive in sun or semi-shade. Plant in a free-draining soil and water only when the soil is almost dry. They can be propagated from tip cuttings, but are frequently grown as half-hardy annuals.
- RHS A-Z encyclopedia of garden plants. United Kingdom: Dorling Kindersley. 2008. p. 1136. ISBN 1405332964.
- The Value of Growing Petchoa SuperCal®. Ornamental News Oct 25 2012