Crocus should be planted as soon as they are available (August / September) in almost any soil, provided it is well drained.
They often look their best in groups beneath deciduous shrubs or trees, but are equally at home when they are planted out entirely in the open, or in rock gardens.
As a general rule set the corms 50mm-75mm deep in heavy soil or 150mm deep in light soil, in both cases space the corms 75mm-100mm apart. It can be advantageous to put some sharp sand under the corms if drainage is questionable.
Do not remove the flowers as they die and do not tie the leaves into bunches or cut them before they are dead; wait until they turn yellow and can be pulled off.