hibiscus tea (jamaica)

My sister told me she heard hibiscus tea had alot of good medicinal uses,lowers high blood pressure,memory boost,aids in digestion,loaded with vitamin C. I order Jamaica at Mexican restaurants cold,I've never had it hot. So we bought the dried hibiscus flowers and I made tea. It is delicious hot or cold! I've been drinking it for the past few days. I found the dried flowers at a Mexican market,my friend says to buy it in bulk(if possible) rather than the packaged flowers as the bulk is fresher. He also says he adds a little lemon. My cousin's husband is from Panama and he adds fresh ginger.