The hibiscus flower is a beautiful, large-petaled flower that can be found growing wild in tropical and sub-tropical climates all across the globe. These lovely buds grow on large shrubs and come in a wide range of colors such as yellow, pink, white, and purple. Depending on the variety, if allowed to grow to its full size, hibiscus can grow up to 30′ tall! Most varieties in the US fall within the range of 12 to 15′ in height and 5 to 10′ wide. Different varieties will perform better in different climate zones, so be sure to research your options before planting.
Thai Red Roselle hibiscus, also know as Jamaican Sorrel or Flor de Jamaica, is grown primarily for the harvest of its bright red calyxes which are found at the base of creamy white flowers. The calyxes and leaves are used in making ruby-colored herbal teas, jams, pies, and sauces. Flowers and young leaves are edible and can be added to salads for a tangy twist. Although perennial in its native tropical range, Thai Red Roselle is most often grown as an annual in more temperate regions. Growing to about 6 feet tall, the striking red-colored foliage and stems will provide beauty and contrast in your garden.
Seed: To grow hibiscus seeds, start by nicking or sanding the seeds. This helps to get moisture into the seeds and improves germination rates.
Seed Depth: 1/4–1/2″
Space Between Plants: 3′
Space Between Rows: 5′
Germination Soil Temperature: 75–85°F
Days for Germination: 7–14
Sow Indoors: 4–8 weeks before average last frost date.
Sow Outdoors: Only in tropical climates with no frost danger, or after average last frost date in areas with a long growing season.
Vegetative: Commonly propagated by taking stem cuttings. Root in a sterile soilless media. Cloned plants will generally be shorter than those grown from seeds and may have a lower yield.
Grows best in a warm topical or subtropical climate and will not survive frosts. Will do well when grown as an annual in temperate climates if started indoors to extend the growing season. In USDA Zones 10 and 11, it’s a short-lived perennial.
Natural: Full sun. Plants are day-length sensitive and won’t bloom until days are sufficiently long.
Artificial: Grows well under HID lamps, especially MH, but will also do well under fluorescents. Needs at least 13 hours of light daily in order to bloom.
Soil: Prefers well-drained sandy or loamy soils with a high amount of organic matter. A pH of between 6.0 and 7.0 will keep plants healthy and nourished.
Soilless: Seeds will germinate in most soilless mixes and seem to do particularly well in mixes containing well-rotted manure and/or perlite.
Hydroponics: Thrives in a media bed hydroponic system.
Aeroponics: Root cuttings will thrive in aeroponic systems.
Water: Requires low to moderate levels of water. Aim for about 1 inch per week.
Nutrients: Requires low levels of nutrients. Sidedress with half the recommended amount of compost tea or balanced organic fertilizer twice per month during the growing season. Avoid adding too much nitrogen, as it will promote foliage growth at the expense of flowering.
Foliar: Use foliar sprays of horticultural oil or insecticide soap to control aphids.
Pruning: Prune the tips of branches when plants are 12–18″ tall to promote branching. When necessary, cut back branches to just above a node or side branch to control plant height.
Mulching: Use mulch once plants are 1–2 feet tall to conserve moisture and suppress weeds.
Rotation: By planting hibiscus at the boundary of a field of a low-growing crop, you will allow it to grow without competition for light. It may also slow the spread of pathogens and weeds and will attract beneficial insects.
Companions: Grows well with mulberry, cinnamon, camellia, and lemongrass.
Harvest: Pick young calyxes by hand when still tender or use garden clippers once stems have gotten tough. Aim for picking about 10 days after flowers open at the beginning or end of the day when temperatures are cooler. Harvesting the calyxes early will promote greater yields throughout the season. You can also pick the edible young leaves and shoots at any time starting about 6 weeks from planting or transplanting.
Storage: Fresh calyxes are usually dried or dehydrated prior to storage. You can keep them fresh in the fridge for 4–7 days while collecting enough to dry a bigger bunch at once. Leaves and stem tips can be stored in the refrigerator for up to a week. Juice can be frozen for later use.
Other names: Hibiscus Flores, Flor de Jamaica, Red drops, Roselle, Rozelle, Sorrel, Red sorrel, Jamaica sorrel, Indian sorrel, Guinea sorrel, Queensland jelly plant, Jelly okra, Lemon bush, Florida cranberry.
Preserve: Dry Thai Red Roselle calyxes in the sun or by using a dehydrator. Store dried calyxes in an airtight container in a cool dark place. Leaves and calyxes can be frozen for later use, either whole or as a puree.The leaves or calyxes are also used to make jelly or syrup, and because the plant contains pectin, there is no need to add any! Be sure to use a pressure canner when canning.
Prepare: Cut open calyxes to remove the seed capsule found at the base of each. After a quick rinse, they will then be ready to use in a variety of ways. Make a bright red, tart tea using either fresh or dried calyxes or leaves, but be sure to boil them and not just steep in hot water. Feeling in the mood for something sweet? When cooked with sugar, they make an excellent pie filling or sauce, reminiscent of cranberry. Yum! If using the leaves, simply rinse and use fresh in salads. They can also be juiced or added to smoothies.
Nutritional: Provides calcium, iron, and B vitamins.
Medicinal: This plant has many medical uses attributed to it, both historically and in modern studies. Various parts of the plant have been used to reduce blood pressure, as a laxative, diuretic, and as a treatment for cardiac, urinary, digestive, and nervous system disorders. May have anti-cancer and antibacterial properties. Extracts have been shown to be active in treating atherosclerosis, liver disease, diabetes, and other metabolic syndromes. Topical uses include healing cracks in the feet and treating boils and ulcers. The tea or juice is even a popular hangover cure.