Content warning Spoilers.
This is solid fantasy book. I give it four stars for the magic, for the good (female!) protagonist, and the Slavic-fairy tale-theme.
For the first hundred pages, I was exited about this book. It felt new and interesting, and I loved the mystery of the valley, the theme of roots. But then around page 100, the protagonist marched into the dangerous wood to free her best friend. She does what nobody has done before, unlocks some powerful magic - and then nothing? The girl she moved earth and sky for is just a mute presence for the rest of the book. This could have been a story about friendship, but there was no connection, no shared moments, nothing. I will have to admit that I was rooting for a love story. I had Chris Riddell's illustration of Neil Gaiman's "The Sleeper and the Spindle" in my head the whole time. But I was disappointed. Instead of the witch-loves-wooden-girl-story we get the powerful, grumpy, oh so mysterious wizard? Oh come on. It wasn't done too badly, but still. The second aspect of the novel that I found frustrating was the protagonists naiveté. In the Temeraire series, Novik wrote suble, complicated politics, even though the protagonist wanted none of it. Here, it was just so simple, so naive. Oh well. One can't have it all.
There were good things: I loved the way the author twisted expectations, mixed in fairy-tales, and the (pseudo-)slavic spells and setting. And whenever the book took place in the valley, it was beautifully written.