What was the title of a children's book featuring a blue dinosaur and his best friend, an apple?

I am trying to find this picture book I read when I was little. It was published in the early 90s and late 80s. It featured a blue, hippo-esque dinosaur who became friends with an apple (an actual apple, it didn't talk or anything). Someone else ended up eating the apple and the hipposaur took it to the hospital. It couldn't be saved, so he buried it, causing an apple tree to grow. I'm a crybaby and I do remember it making me cry (not that that helps with identifying it). Twenty Steven points to anyone who can identify it!