This cheery summer bloomer looks like a small petunia, to which it is related. It is native to Brazil and Peru, and its garden forms are hybrids. It was once called Million Bellsthe name of an early and still-popular seriesbut now just Calibrachoa. Plants have tiny, closely set leaves and a profusion of small, single or double flowers that fall off as they fade; blooms keep coming all season long. Colors include solids, bicolors, and veined patterns in shades of white, yellow, orange, apricot, red, pink, blue, burgundy, lavender, and purple. For hybrids between Calibrachoa and Petunia, see x Petchoa.
There are many excellent calibrachoa series with names like Cabaret, Callie, Colorburst, Can-Can, Million Bells, and Mini Famous. They sometimes differ by color range and pattern, but there is overlap. The heat- and disease-resistant Superbells series, for example, includes about 30 selections in a wide range of colors and habits.
Trailing calibrachoas in all series grow lower (usually 37 in. high) and spill out to the sides, while mounding forms can be 8 to 15 in. high, and grow about as wide as high. Intermediates are just that.
Calibrachoas perform superbly in containers but struggle in garden beds that have less than perfect drainage. Consider them perennials only where frosts are nonexistent or light.
Calibrachoas are generally less hungry and thirsty than petunias grown in the same conditions, but because they are at their best in containers, regular watering and fertilizing are still the rule. (Avoid using water-retention gels.) They do best in slightly acidic soil and quickly decline in alkaline soil. The plants' wiry stems are less subject to breakage than are petunia stems, and tobacco budworms seem uninterested in foliage and flowers.