This reminds me a bit of "The Scarlet pimpernel", but better! ;) And not just because of the flower-related title, hehe. Something you mentioned also reminds me of Violet Jacob's novel... it really is interesting to think about all her possible influences!

Also: characters finding happiness later in their lives seems to be a theme in Broster's writing. I first saw it in "Sir isumbras", but now, with a little effort, i see it everywhere, and it's nice, even if that happiness is not long-lived, like in Keith's case in TFOTH, it's totally valid *cries forever*

Anyway! This review was great, thanks for sharing it! I totally want to read this too! :D