The chrysanthemums group was once a vast genus but has recently been split up by botanists. Chrysanthemum, itself was also removed as a name and for a while was called Dendranthema and plants can often still be seen labelled as such. Now the name refers almost exclusively to the popular garden chrysanthemums. There are literally thousands of these and more appear all the time.
The original chrysanthemum was a typical daisy shape with a central disk with a single row of petals radiating out from it. Gradually they have been bred in a variety of shapes, many of them doubles with a vast number of petals. The main flower forms are single, anemone-centred, full-reflexed, incurved, intermediate, pompon, quill-shaped, reflexed, spider-form, and spoon shaped.
The hardy chrysanthemums, which are mainly singles, can be left outdoors and are usually grown in ornamental borders. The other forms are mainly grown for cutting and for exhibition and are grown in their own beds where they can be tended individually, rather with other plants.
They are usually started in the late winter from cuttings taken from the stools of the previous year's plants that have been overwintered inside. They are planted out after the frosts have passed. They usually need support from canes.