Its name may be something of an exaggeration, but million bells, or Calibrachoa, certainly is profuse. However, although it is potentially perennial, it is usually grown as a warm season annual, so it only has a few months from spring to autumn in which to bloom with a million flowers. Many plants combined might be up to the task.
The tiny flowers resemble petunias more than bells. Actually, the entire plant grows something like very compact petunias, which they are obviously closely related to. The stems are too limber to stand half a foot tall as they spread to about a foot wide. The small and unremarkably hazy green leaves are adequate backdrop for bloom.
The bloom is the remarkable part, displaying all sorts of shades and hues of red, yellow, blue, purple, orange, pink and white. There are not many colors left out. Just like petunia, million bells cascades nicely from pots. Unlike petunia, it does not benefit from deadheading (removal of deteriorating flowers). What is good for petunia is generally good for million bells, although a slight bit of shade is somewhat more tolerable. They want rich soil, regular watering and regular application of fertilizer. (Monthly application of common slow release fertilizer is probably as good as anything fancy.)