Flower and Thorn by Rati Mehrotra

One girl. One boy.

A promise broken.

A magic stolen.

Irinya has wanted to be a flower hunter ever since her mother disappeared into the mysterious mist of the Rann salt flats one night. Now seventeen, Irinya uses her knowledge of magical flowers to help her caravan survive in the harsh desert. When her handsome hunting partner and childhood friend finds a priceless silver spider lily--said to be able to tear down kingdoms and defeat an entire army--Irinya knows this is their chance for a better life.

Until Irinya is tricked by an attractive imposter.

Irinya's fight to recover the priceless flower and to fix what she's done takes her on a dangerous journey, one she's not sure she'll survive. She has no choice but to endure it if she hopes to return home and mend the broken heart of the boy she's left behind.