'irregular-blooming' originates from the combination of 'irregular' and 'blooming', where 'irregular' meant 'not regular' and 'blooming' referred to 'the process of flowering'.

'irregular' changed from the Latin word 'irregularis' and 'blooming' from the Old English 'blōma', eventually forming the modern English term 'irregular-blooming'.

Initially, it meant 'not following a regular pattern in flowering', and this meaning has largely remained the same in modern usage.