The park has 42 / 3 = <<42/3=14>>14 pink crepe myrtle trees.
It has 2 red trees, so it has 14 + 2 = <<14+2=16>>16 pink and red trees.
Therefore, there are 42 - 16 = <<42-16=26>>26 crepe myrtle trees that have white flowers when they bloom in the park.
#### 26