She has written dozens of childrens' non-fiction books and has lately written some lovely novels in verse for children and teens.

Spinning Through the Universe is the observations of the children in a fifth-grade classroom, each telling his own story. Ten is such an interesting age, and I think anyone who has ever been ten will enjoy this. Here is a general observation on children from the teacher:
"... Every child is like
A little world with ever-changing weather,
Nights and mornings. And somehow, here we are,
Spinning through the Universe together."

Keesha's House is a similar style, only aimed at teens. Six teens for various but familiar reasons cannot go home and need a safe place to stay until their circumstances improve. Beautifully written, but a whole lot of angst.

She has also written two historical romances.

The Braid is set in 1850 Scotland and Cape Breton. Two young sisters have become separated and take turns narrating their stories in braid-like fashion. The story itself is very interesting as both girls take very different, and dangerous journeys. This would be a lovely novel in prose (and probably has been). But writing it in poetry really makes it special.

Crossing Stones is about two neighboring Michigan families faced with the terrible events of 1917-18, when the nation went to war and experienced a catastrophic epidemic. It is narrated by a young girl, her brother, and their young neighbor. This story is very predictable but I couldn't put it down anyway.

I recommend beginning with the back of the book, with Frost's notes explaining the structure of each poem. These books certainly can be enjoyed without knowing they were written in, say, Italian sestina. But it has been a long time since I have studied poetry and I appreciated understanding how she built the verses. Poetry is such a disciplined art and says so much in just a few words. I enjoyed these books enormously.