Add dried hibiscus flowers, sugar, and water to a medium saucepan over medium heat. Stir occasionally until the sugar has dissolved and the mixture reaches a simmer.
Stir in the cinnamon stick, cardamom pods, and cloves and bring to a boil.
Reduce the heat to low and simmer for 10 minutes, stirring occasionally.
Turn off the heat and let steep for 1 hour before straining with a fine mesh sieve. Transfer the syrup into an airtight bottle or jar and store in the fridge.
Notes
Keep in the fridge for up to 3 weeks in an airtight container.
Make a simple agua fresca by adding a bit of the syrup to some water. Best served chilled or over ice.