The Night Gardener by Terry and Eric Fan
The book that won the actual 2017 Randolph Caldecott Medal was:
Radiant Child: The Story of Young Artist Jean-Michel Basquiat by Javaka Steptoe
And the Caldecott honors were:
Leave Me Alone! by Vera Brosgol
Freedom in Congo Square by Carole Boston Weatherford, illustrated by R. Gregory Christie
Du Iz Tak? by Carson Ellis
They All Saw a Cat by Brendan Wenzel