3 pounds fresh blueberries, crushed
1 1/2 pounds pitted fresh sweet cherries, crushed
1 (11 ounce) can Mandarin orange segments, drained and crushed
1/4 cup lemon juice
1 (1.75 ounce) package powdered fruit pectin
5 1/2 cups white sugar
Combine the blueberries, cherries, oranges, lemon juice, and pectin in a large pot; bring to a rolling boil. Stir in the sugar until it dissolves completely and the mixture returns to a rolling boil; boil 1 minute and remove from heat. Pour into hot, sterilized jars and top with sterilized lids. Secure lids with bands, process for 5 minutes in a boiling water bath. Allow jars to cool slowly, creating a vacuum seal. Allow to sit at room temperature 1 to 2 days to allow jam to set. Refrigerate after opening.