Often there are sales on frozen wild blueberries and when living in a big city frozen is more economical.

Frozen fruit and veggies are absolutely a wonderful alternative to field-fresh. They are picked at the peak of ripeness/freshness and then flash frozen within hours. If you don't have access to fresh, or its off-season, frozen is the way to go. Just be sure to look at the ingredient list, and make sure only the fruit/veg is listed; no additives like sugars or salts.

That's right, DonnaMae! You could use them in the recipe mostly defrosted, so they wouldn't give off too much liquid while boiling.