Creamy Broccoli Salad with Apples and Cherries

medium broccoli crowns, trimmed of stems (about 5 cups of bite-sized pieces)

fresh cherries, pitted and halved*

large Granny Smith Apple, chopped (about 1 1/2 cups)**

ribs, celery, chopped (about 1 cup)

red onion, chopped

sunflower seeds

Dressing:

light sour cream

plain, low-fat Greek yogurt (I used Fage)

white vinegar

sugar

salt and pepper