In a bowl, combine seltzer water, the juice of 1 lime, and maple syrup
Mash ½ cup of blackberries in a cup
Then add the blackberry mash to a large jar, along with the seltzer water mix, and rosemary sprigs. Make sure to bruise some of the rosemary stems to release the flavors.
When ready to serve, pour into glasses and top with the rest of the blackberries. Garnish with rosemary.