Hibiscus (Hibiscus sabdariffa), also called roselle, is a short-day plant usually grown in tropical and subtropical areas. In the United States, it has been grown commercially in Florida, California, Louisiana and Kentucky. Many home gardeners have figured out how to grow Hibiscus successfully as a warm weather annual in Oklahoma, New Jersey and even farther north.
In temperate Zones, start hibiscus in pots at the same time as you would tomatoes. When seedlings are 3 to 4 inches high, transplant them to a sunny spot in the garden. Space plants 3 feet apart in rows 5 feet apart. Hibiscus grows well in soil with a high level of organic matter, but too much nitrogen will delay flowering until too late in the season. Keep plants unmulched, evenly moist and well-weeded until they are 1 1/2 to 2 feet high. At that point, mulch the plants to keep weeds at bay for the rest of the season.
The small leaves and tender branch tips are a refreshing addition to fresh salads. You can also use them to make a tea or jam similar to the ones from calyxes. You don’t need to add pectin because hibiscus leaves contain 3 percent pectin. Hibiscus tea needs to be boiled to get the deep red color and great flavor.
On our central Virginia farm, flowering of our preferred ‘Thai Red’ roselle variety begins in late July to mid-August, and continues until frost. We cover plants with Reemay or tarps during early light frosts to keep the harvest going well into October.
The hibiscus calyxes are most easily harvested when fully grown but still tender. At this stage, they can be snapped off by hand. Use clippers to harvest stems that have hardened. A second advantage of harvesting early and often is increased total production of calyxes. Although, picking a variety with less day length sensitivity may be the most important factor affecting yield in temperate areas.
Calyx production on our farm has ranged from 1 to 2 pounds per plant. (Expect less if you are waiting for the lower fruits to mature seeds before beginning the harvest, and expect more if harvesting while the calyx stems are still tender.)
It takes 10 to 12 pounds of fresh calyxes to make 1 pound of dried calyx for refreshing hibiscus tea. For a home gardener, this means that three to six well-spaced plants would produce half a pound of dried calyxes, as well as delicious salad additions from young leaves and stem tips all summer.
Ira Wallace is on the board of the Organic Seed Alliance and works and owns the cooperatively managed Southern Exposure Seed Exchange where she coordinates variety selection and seed grower contracts. Southern Exposure offers over 700 varieties of open-pollinated heirloom and organic seeds selected for flavor and regional adaptability and helps people keep control of their food supply by supporting sustainable home and market gardening, seed saving and preserving heirloom varieties. In addition, Ira is a member of Acorn Community, which farms over 60 acres of certified organic land in Central Virginia, growing seeds, alliums, hay and conducting variety trials for Southern Exposure. She is also an organizer of the Heritage Harvest Festival at Monticello, a fun, family-friendly event featuring an old-time seed swap, local food, hands-on workshops and demos, and more.