Roselle

Hibiscus sabdariffa

Malvaceae

The crimson sour calyx behind agua de jamaica — a cooling, tart drink for heat and blood pressure folklore.

Culinary calyx. Grocery 'hibiscus tea' is usually this species, not the landscape shrub.

Parts used: Fleshy calyx
Traditional notes: Cooling summer drink · Mild blood-pressure folklore · Tart flavoring
Grow · USDA 6b: Tender annual. Needs heat. Start indoors 6–8 weeks before last frost, or grow in the Deep South as a summer crop. In work: May · Jun · Jul · Aug · Sep
Harvest: Pluck calyces when fleshy, a few days after the flower drops.

Heat and water. Roselle is a tropical annual in most of the US.
Harvest the fleshy calyx after the flower drops, while it is still plump.
Start indoors if your summer is short.

Safety

Already-low blood pressure Pregnancy at medicinal — not food-drink — dose without advice

Lore

Roselle, karkadé, agua de jamaica — the same calyx in different heat. The red is the plant, not a dye pack. Pharaohs drank a version; Caribbean groceries still sell the bags.

The Herbarium — a teaching catalog, not a clinic. Traditional use is history, not a prescription. USDA 6b dates are a week either way, not a promise. Do not eat, drink, or harvest a plant you cannot name.