Put the dried hibiscus flowers and ginger, into a measuring cup or pot big enough to hold 8 cups. Cover with the boiling water, and steep for 5 minutes or until you have the desired strength. The longer you leave it to steep, the stronger and more intense the flavor will be.
Strain the tea into a jug or carafe through a fine sieve. It will be a gorgeous dark red. Stir in the agave or honey to taste. Serve hot or poured over ice.