The bulbs of Autumn crocus (colchicum), also known as meadow saffron, need to be planted in late summer.
They start flowering within a few weeks, producing clusters of violet, crocus-like flowers with leaves following later.
C. 'Waterlily' is a bigger-than-average cultivar with pretty double flowers 20cmx10cm; C. byzantinum is stronger but smaller, with more flowers.
Autumn crocus need well-drained soil containing plenty of organic matter and can be planted in sun or light shade.