Combine plums, apples, pears, water, lemon ring, and lemon juice in a large stainless steel or enamel saucepan.
Bring to a boil over high heat, cover, reduce heat and cover for 10 minutes or until fruit is softened.
Add sugar to fruit and return to a boil, stirring constantly until sugar is dissolved. Boil rapidly, uncovered until mixture will form a gel, about 30 minutes, stirring occasionally. Stir in cinnamon and ginger.
Ladle into hot jars, remove air, add to come to 1/4" headspace, wipe rims, add hot lids and rings. Process for 10 minutes in a water bath at a full boil.
Makes 4 cups