flowering has 6 distinct synonyms spread across 2 of its 3 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. Its one recorded opposite is flowerless.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
the time and process of budding and unfolding of blossoms
a developmental process
“the flowering of antebellum culture”
having a flower or bloom
“a flowering plant”
Synonyms, antonyms and the broader and narrower relations for flowering come from Princeton University’s WordNet. Full sources and licences.