Combine water, sugar, ginger root, cloves, and allspice in a small saucepan; bring to a boil.
Reduce heat, and simmer 15 minutes or until sugar dissolves, stirring occasionally.
Strain sugar syrup through a sieve into a bowl; discard solids.
Cover sugar syrup, and chill.
Divide watermelon, cantaloupe, and blueberries evenly among 6 dessert dishes.
Spoon 1/4 cup sugar syrup over each serving.