Combine the hibiscus tea, gin, Blackberry Simple Syrup, lemon juice and creme de mure in a pitcher. Taste for balance and adjust as necessary. Pour into rocks glasses over fresh ice, garnish with a blackberry and serve.
First make the simple syrup: Combine the sugar and 1 cup water in a small saucepan and bring to a boil. Cook, stirring, until the sugar dissolves. Remove from the heat and let cool completely.
Add 1 cup of the cooled simple syrup to a blender with the berries and blend until smooth. Strain out the seeds and pulp before using.
Keep any remaining simple syrup in the refrigerator, covered, for up to 1 week.