Mountain Laurel look great when planted with Rhododendron and/or Azalea. They have smaller leaves but boom almost at the same time as the Rhodies, early May for us in NC. If you love Mountain Laurel or want to try the for the first time, be sure to plant them very high and use well draining soil so that thier roots do not stay wet as they will rot very quickly. In the nursery, we water them very lightly and not after 2pm.
Be sure to use a well drained soil medium when planting any Mountain Laurel as they prefer fall planting with less watering than you might think. In NC our soil is clay so we prefer to use pine bark soil conditioner when planting Camellia, Rhododendron, Mountain Laurel, and Azalea.