expression, godan verb (-ku)
have a lively conversation; reminisce; talk enthusiastically
Used when a conversation becomes animated and enjoyable, often because the participants share common interests or memories. The image is of flowers blooming in the talk.
昔の話で話に花が咲いた。
We had a lively conversation reminiscing about old times.
趣味の話になると、
Whenever the topic turns to hobbies, the conversation always gets lively.