'many-flowered' originates from English, specifically as a compound of 'many' and 'flowered', where 'many' ultimately comes from Old English 'manig' meaning 'many' and 'flower' comes via Old French (flor/flower) from Latin 'flos' meaning 'flower'.

'many' changed from Old English 'manig' to Middle English 'many'; 'flower' changed from Old French 'flor/flower' to Middle English 'flower', and the adjectival/past-participle form 'flowered' was formed by adding the suffix '-ed', yielding the Modern English compound 'many-flowered'.

Initially it meant 'having many flowers' and this core meaning has been retained into modern usage.