The tree used to be grafted - one half was the crab apple that had pink blossoms and one half was a green apple that had white blossoms.
A couple years ago, we had to cut down the green apple part of the tree after it was damaged during an ice storm.
The crab apple part has managed to continue to grow providing food for the bees in the spring; and a waiting and relaxing area for the birds while they are visiting the feeder on the mudroom roof.
Interestingly, there is another crab apple tree that we planted nearby. A few years ago I noticed a different type of tree growing right next to it. Last year there was an apple on one of the branches. It was the green apple tree...except next to this new tree. Hopefully this year both parts of the tree bloom at the same time. It's so eye-catching when a tree has two different colors of blossoms.