It is impossible to fit enough information about chrysanthemums into just a few sentences. Centuries of breeding have produced too many cultivars to document. Flower color ranges through many shades and hues of yellow, orange, red, pink, bronze, cream, lavender and almost purple, as well as white. (True purple is purportedly lacking.) Many have yellow centers. The deeply lobed leaves are strongly aromatic.
Flower form is as variable as color is. Some are small domed buttons that bloom in sprays of many blooms. Others are round pom-poms. There are all sorts of daisy types. Spider mums have weirdly elongated ‘petals’, (which are actually ‘ray’ florets). Those that bloom singly are bigger than those in sprays. Some of biggest and most billowy seem to be too heavy for their own stems!
If they get what they want, chrysanthemums can be surprisingly reliable and easy to grow. They do want regular watering, regular application of fertilizer, and richly organic media, such as potting soil. In fact, they are popularly grown in pots because they prefer potting media to garden soil. Potted plants can be brought in while blooming, and then retired to the garden between bloom phases.
Only a few decades ago, when horticulture was taken more seriously, potted blooming plants like chrysanthemums, orchids, azaleas, hydrangeas, lilies and even poinsettias, got the respect that they really deserve. Now they are more commonly purchased in full bloom, enjoyed only as long as their bloom lasts, and then discarded as their blooms deteriorate.