In a blender, add the blueberries, water, and ¼ cup of sugar. Blend until smooth.
In a large bowl, gently whisk together the heavy whipping cream and remaining ½ cup of sugar, until all the sugar has dissolved.
Alternate pouring the blueberries and cream into popsicle molds until all the mixtures have been used. Freeze for at least 4 hours, then remove from molds, wrap each popsicle in wax paper and place in a plastic bag for storage in the freezer.