Zora Neale Hurston's use of personification is anything but random. In most cases, the personification used is a direct element of the folklore that Hurston employs in the novel or is meant to emphasize the folklore.
One of the clearest examples of this idea is the recurring personification of death that appears throughout the novel. For example, in Chapter 8, we learn:
"So Janie began to think of Death. Death, that strange being with the huge square toes who lived way in the West. The great one who lived in the straight house like a platform without sides to it, and without a rood. What need has Death for a cover, and what winds can blow against him? He stands in his high house that overlooks the world. Stands watchful and motionless all day with his sword drawn back, waiting for the messenger to bid him come. Been standing there before there was a where or a when or a then."
You might look for similar personification throughout the novel for such natural elements as night, the moon, the sunrise, the sunset, and of course the pear tree. And also for such elements as blues music, gossip, and love.