Looking for a fantasy book with young male protagonist protecting magic seed

Years ago I read a book that featured a pretty typical “young boy is plucked from obscurity to be chosen one destined to protect the world from magical evil” (that might have included some found friends/comrades along the way), from what I can remember surrounding a plot about a magical tree that had died or been destroyed by this major evil figure (male, as I recall) but had a single magical seed left that could sprout another magic tree.

The final “battle” scene I believe included a shock reveal of the protagonist’s mother (who had been believed to be dead?), the realization that the evil antagonist was the protagonist’s father, and the image of the evil antagonist keeping this magic seed as an earring in his ear. I can distinctly remember the description of the magic seed earring as spiral in shape.

In the end the protagonist manages to come into possession of the seed and plants it possibly outside a castle in the very last pages of the book.

If anyone has even the slightest suggestion of what this book could be, I would be terribly appreciative. I’ve rolled this plot around in my head and my google searches for years with no luck, and I’d love to have a title to go with it.