Onion Snow or Cherry Snow?

Heard on the radio the other day that snow in the South in springtime (how much of that do they get, I wonder?) is called "onion snow," because it arrives so late that the onions are already up. Well, my onions are up, too, but in the orchards there was white on the ground and white on the branches. Cherry snow, I'm thinking. Snow in May: Up North weather.