I live in Zone 5 in an area where we get a lot of snow so I am among those who need early spring blooms to keep my spirits up. The number one favourite in my garden is a rhododenron called "April Mist" whose name describes it perfectly. I think I would called it an azalea but it was sold as a rhododendron.
It does bloom, prolifically, in April and the entire shrub is absolutely smothered in the loveliest double, fluffy, very pale pink blooms. The first year it bloomed fully I stood there in absolute amazement that anything so fragile-looking could appear while the weather was still really nasty some days.