Blueberries and saskatoons do not set nicely in jam so you can help the process by adding rhubarb.

Ingredients

3 cups chopped or pureed rhubarb
3 cups crushed fresh blueberries or saskatoon
6 cups sugar
2 Tbsp lemon juice
2 Tbsp butter
2 (3 oz) pouches of liquid pectin

Directions

Combine prepared rhubarb and blueberries in a large saucepan. Add sugar and lemon juice. Mix and add butter. Bring to a full, rolling boil over high heat. Boil hard for exactly one minute, stirring constantly. Remove from heat. Stir in pectin. Skim foam (which should only occur if not being continuously stirred) and fill jars to 1/4 inch from top.