Hi- I think most of the Michigan growers will have fresh sour cherries this Saturday at the Evanston's farmers market. If you are ambitious you can go to my sister's fruit farm outside of Coloma Michigan. You get off at exit 39 on I-94. Everything is early this year, and she is all out of upick sweet cherries, but she will have upick sour cherries through 7/5. Her upick is open from 10:00am-5:00pm, but I would call first. She still has already picked sweet and sour cherries available at her fruit stand, which is located right off exit 39. Her sour cherry upick is about a mile South of the fruit stand. Here is a link to her website:
http://fruitacresfarms.com She will have upick peaches starting July 18. There is at least one person that sells at the Evanston market that sells frozen pitted sour cherries every week in cans. Her name is Sally Stover, and she is located at the very last spot in the first row which is next to Maple. There might be some other growers that carry frozen pitted cherries, but most of the Michigan growers that sell at the Evanston farmer's market, only sell sour cherries when they are in season, and usually sell them by the quart, although I am sure they would give you a deal if you wanted to buy 10 pounds or more.
Another place you can probably get frozen cherries is Sara Lee Thrift shop. I know the one on Dempster in Skokie carry's stuff from Coloma Frozen Fruit, and I assume they carry their frozen cherries. BTW a lot of the stuff packaged by Coloma frozen fruit comes from California, although I am sure that all their sour cherries come from Michigan. Michigan is the largest grower of sour cherries in the country.
The person who does not hit the farmer's markets because she belongs to a CSA. None of the CSA's raise cherries, apricots or peaches, and very few of them raise blueberries and apples. Hope this helps, Nancy