Is the sentence okay?

Flowers bloom splendidly for heroic deeds, including, but not limited to, mine.

or:

Flowers bloom splendidly for heroic deeds, including (but not limited to) mine.

Reads fine to me. I'd put another comma after limited - but that's a matter of personal style.
*Edited to say that David is technically more grammatically correct, splendidly is the adverbial form that describes the verb bloom, but I like the way yours sounds better.

Is this a line of a poem?

Just a sentence in a conversation.

Thank you both.