"Flowery" language includes many adjectives and adverbs. Prose or Poetry is marked often as "flowery." For example: "The big, beautiful sun shone like a million diamonds upon the deep blue sky" is a "flowery way" to write that "It was a sunny day."

Agree above. Flowery also means unnecessary. e.g. in English, it's common for people to write extra phrases which are unnecessary e.g. "in order to" (you can just write "to") "it is important that" "it should be said that" etc...