Combine juice, blueberries and sugar syrup in a blender. Puree until most of the berries are chopped. Pour into mold and cover. Freeze 2 to 3 hours.
Gently insert ice pop sticks into pop mold, keeping as upright as possible. Freeze at least another 4 hours or overnight.
Remove cover. Run outside of mold under warm water and gently pry pops from mold. Place in freezer-safe resealable plastic bag and store in freezer until serving.