These constitute a genus of about 45 species and a number of cultivars. They are not related to crocuses but are known as autumn crocus because of the shape of their flowers, which is the familiar goblet shape of crocus. Although there are some species that are small and a similar size to many crocuses these are mainly grown by specialists, while the more common varieties are of a much larger size, some being up to 20cm (8in) tall. The colours are mainly varieties of pink, but there are also darker ones that merge into purple, as well as white and yellow ones.
An alternative name for these plants is ‘naked ladies’. This name is given because the flower appears through the earth by itself without any foliage. The leaves do not appear until the following year. They are unlike the leaves of true crocuses because they are quite broad and long. Some gardeners feel that the leaves are unattractive and so plant them in a position where the flowers show in autumn but the foliage is covered by other plants in the spring. Colchicums are good for naturalizing. They will grow in full sun or light shade. They like a fertile, well-drained soil that does not dry out completely.