Hibiscus spp. (Malvaceae – Mallow family)
Hibiscus is not native to Ibiza, but because of its popularity as a cultivated plant, because it thrives in the Mediterranean climate, and its potential medicinal value, I have decided to include it here.
Hibiscus is a widely distributed genus of more than 300 species native to tropical, subtropical and warm temperate regions. These include herbaceous plants (annual and perennial), woody shrubs and small trees. Several species are cultivated as ornamental plants. The most obvious distinguishing feature of hibiscus are its large, colourful, trumpet-shaped flowers with five or more petals and protruding pistil surrounded at its tip by numerous stamens. Flower colour can be white to pink, red, blue, orange, peach, yellow or purple.
Hibiscus sabdariffa (roselle), the species known for the drink karkade* , is also the one most studied for its medicinal value. It is native to India and Malaysia but is now grown in various tropical and subtropical regions. Aside from this, I have decided to limit my discussion to three species which because of their hardiness to lower temperatures are commonly grown in Europe: Hibiscus syriacus (rose of Syria, rose of sharon), well-known throughout the Mediterranean, Hibiscus rosa-sinensis (Chinese rose mallow) and Hibiscus moscheutos (swamp rose mallow).
All of the aforementioned species are edible and/or can be used for medicine (see below). The flowers, sepals and leaves may be eaten, even the stems may be chewed. Some say all species of hibiscus are edible, although I would not like to repeat this without definite scientific confirmation.
[* Karkade: a popular “tea” (infusion) in North Africa made from the calyces (the part of the plant comprising the sepals that surrounds the base of the petals) of roselle. It has a deep red colour, a tart flavour, and is rich in vitamin C.]
Although it is frequently said that all hibiscus species are edible, it is better to be safe than sorry. Please be sure of correct identification before using a hibiscus plant to eat or for medicine. If you are not absolutely sure about your hibiscus being one of those in the following list, do not eat it or use it for medicine.
The following species of Hibiscus are listed as edible on the Plants for a Future website [1]:
Hibiscus acetosella, False roselle
Hibiscus cannabinus, Kenaf
Hibiscus diversifolius, Swamp hibiscus
Hibiscus heterophyllus, Native rosella
Hibiscus mutabilis, Cotton rose
Hibiscus rosa-sinensis, Chinese hibiscus, Chinese rose mallow
Hibiscus sabdariffa, Roselle
Hibiscus sinosyriacus, Rose of Sharon
Hibiscus syriacus, Rose of Sharon, rose of Syria
Hibiscus trionum, Flower of an hour
Hibiscus moscheutos, Swamp rose mallow (no reports of edibility but is listed as having medicinal properties)
Traditional Uses in Spain
There are no traditional uses in Spain.
Vital Qualities
In Ayurvedic (Indian) medicine Hibiscus is considered to have astringent and bitter tastes and to be Cooling and Drying. It reduces vitiated Pitta and Kapha doshas [2].
In Traditional Chinese Medicine (TCM) it is regarded as sour in taste and Cooling in nature“` [3]`
As with other members of the Mallow family, parts of the plant (and especially the bark and root) contain a significant amount of mucilage which is Moistening rather than Drying, so we may conclude that the plant has an ambivalent character in this regard, which perhaps depends on the part used.
What to Use It For
The most studied species is H. sabdariffa and this has been studied most for its ability to lower high blood pressure. Studies confirm the validity of this use, which is traditional in many parts of the world. Some animal studies indicate that H. syriacus and H. rosa-sinensis also produce the same effect, although this must be regarded as preliminary information and potentially but not necessarily applicable to humans.
Other potential benefits of H. sabdariffa, which according to a few studies seem to be mirrored in H. syriacus and H. rosa-sinensis are:
- Reduces high blood fat levels (including cholesterol and triglycerides).
- Reduces elevated blood sugar.
- May help manage metabolic syndrome.
- May protect the liver (e.g. against fatty liver, and liver damage from chemotherapy drugs).
- Has antibacterial, antifungal, antiinflammatory and antioxidant* properties.
- May have anticancer properties.
[* Hibiscus contains anthocyanins (the plant’s red pigments), flavonoids, phenolic acids, and organic acids, many of which compounds act as antioxidants. Antioxidants protect the body’s tissues from damaging free radicals, which age the tissues and make them more prone to degeneration and disease.]
Other Uses
The other traditional uses of the various hibiscus species are many and various. The ones that seem to be quite constant across species, geography and culture are as follows.
Chest complaints: H. rosa-sinensis, H. syriacus and H. moscheutos have all been used traditionally in several regions of the world for respiratory complaints like coughs, colds, bronchitis and catarrh. Various parts of the plant are used – flowers, leaves, stem, roots – taken internally as infusions or decoctions. Hibiscus combines several properties which may account for its benefits for the lungs and airways: demulcent (soothing to inflammation), anti-inflammatory, antibacterial and expectorant (this latter reported in H. syriacus according to the Plants for a Future database [5]).
Gynaecological and obstetric issues: In various regions H. rosa-sinensis has been used to stimulate menstrual flow (e.g. in cases of amenorrhoea), regulate the menstrual cycle, treat dysmenorrhoea, or stop excessively long menstrual bleeding (menorrhagia). Mostly the flowers have been used but also the bark, leaves and stem. The most common preparation is some kind of water extract (like an infusion or decoction), but also the juice has been used. Substances which stimulate menstruation may also stimulate uterine contractions, and thus may be used to induce labour (as in Northern Ireland), stimulate the expulsion of the placenta (e.g. East Indies) or to provoke an abortion (several regions). In Peru in addition to their use as an emmenagogue (a substance which promotes menstruation), the flowers are also taken as a contraceptive (warning: Do not rely on this!). In classical Chinese texts, H. syriacus has been reported to be used in treating leukorrhoea and vaginal or uterine bleeding [6]. In the light of its action as an emmenagogue and purported contraceptive use, hibiscus of any kind must be avoided in pregnancy and when trying to conceive.
Digestive issues: Stomach pain, diarrhoea, dysentery, poor digestion. In various regions the leaves, flowers or bark are taken for these conditions as an infusion/decoction or juice. According to A barefoot Doctor’s Manual [5], a decoction of the flowers of H. syriacus is indicated in China for “bloody stools accompanied by much gas” (I assume this can be translated as inflammatory bowel disease and/or dysentery), and a 2007 Korean study which scoured 24 classics of Oriental medicine for references to H. syriacus found reported an indication to be taken internally in bleeding intestinal diseases. The demulcent, astringent, anti-inflammatory, antibacterial and haemostatic (stopping bleeding) actions of hibiscus all come into play here. A decoction of the root bark of H. syriacus has been used traditionally for intestinal worms.
Urinary inflammation: A hot water extract (decoction/infusion) of the stem/flowers of H. rosa-sinensis is taken as a diuretic and demulcent in India. H. syriacus, too, is known to be both diuretic and demulcent. These actions suggest to me a use for urinary tract inflammation (like cystitis and urethritis). Indeed H. moscheutos has established traditional uses in its native range of North America in the treatment of urinary ailments such as inflammation of the bladder (cystitis). Hibiscus has anti-bacterial and antifungal properties which would enhance its benefits for the urinary tract in cases where symptoms are associated with infection. (That is used for gonorrhoea in the Cook Islands attests to this.)
Bleeding: Hibiscus has an astringent character that is responsible for its ability to stem haemorrhage. This property has been put to use traditionally in gastrointestinal bleeding and uterine haemorrhage, as described previously.
Skin irritation/inflammation: The astringent, demulcent, emollient, antibacterial, and antifungal actions of hibiscus have been exploited in traditional medicine around the world to help skin conditions like itching, scabies (a rash and itching due to a mite infestation), fungal infections and boils. the use of hibiscus for skin problems is external, most usually as a poultice of the flowers.
Problems of the anus and rectum: H. syriacus was mentioned in classics of Chinese medicine as a treatment for haemorrhoids, anal fistula and prolapse of the rectum [6]. It’s demulcent, anti-inflammatory, astringent* and antibacterial effects could well explain these uses, effects that it shares with other hibiscus species.
[* The quality of astringency in medicinal plants has the effect of toning lax tissue, reducing swelling and congestion, making tissue less susceptible to infection, and it even produces a certain antimicrobial effect in its own right.]
Important note!!!: Some of the conditions mentioned above are potentially serious, even life-threatening. Always go to your doctor for a proper diagnosis before embarking on any form of treatment.
When and How to Harvest
The most used parts of hibiscus species in general are the flowers, but H. sabdariffa is harvested principally for its calyces (sepals). H. sabdariffa flowers in the autumn, H. syriacus in late summer, H. moscheutos in summer and early autumn and H. rosa-sinensis throughout the year. The flowering period lasts two or three weeks in the case of H. sabdariffa, but for H. syriacus and H. moscheutos new buds produce flowers over a long summer blooming period. Flowers only last for 1 or 2 days. Pick them when they have just opened, in the morning on a sunny day, after any dew has evaporated.
If you are lucky enough to have a roselle (H. sabdariffa), to harvest the calyces (singular calyx: the “cup” formed from the sepals), wait till 3 to 7 days after the flowers have dropped. Then cut them from their stems with clippers, slit them down the middle and remove the single pea-like seed pod. They may then be dried and stored.
I can find no information about when to harvest the other plant parts specifically of hibiscus, but the general rules for harvesting medicinal plants are as follows:
- Harvest leaves and stems when foliage is healthy and abundant enough to sustain growth but before flowering.
- Harvest roots in late autumn or early winter.
- Harvest bark in the spring. Do not take too much bark from each stem and never take bark in a circle all around a stem, as this will cause the death of the parts above that point.
Easy Household Use
In many of the studies of H. sabdariffa for high blood pressure a simple infusion has been used, with dosages of dried hibiscus ranging from 2 to 20 g per day for four weeks. No standard dose has been established. I would suggest using a teaspoonful (that’s about 3 g) of ground dried hibiscus per cup of boiling water. Let it steep for 10 minutes before drinking. Drink one cup per day. If necessary (that is if results are insufficient), increase this to two or three times a day.
For other hibiscus species and/or other uses, I can do no better than suggest following traditional practices, that is, for internal use an infusion (for soft plant parts) or decoction (for hard plant parts), and for external use a poultice or compress (see Preparations). As the species of hibiscus discussed in this chapter have minimal or no toxicity except perhaps with prolonged use at high doses, I would suggest that standard doses are appropriate (see Doses).
When Not to Use It
The following information is specifically about Hibiscus sabdariffa taken as a tea. I have been unable to find reports of any negative effects from the use of other species of hibiscus. On the basis of similarity of chemistry, actions and effects with what is known of other species of hibiscus, it seems reasonable to assume that the cautions would be similar.
Hibiscus tea is generally well tolerated at normal doses (up to 3 cups per day of the infusion). However, prolonged use at high doses might harm the liver.
Avoid taking hibiscus in the following situations:
- In pregnancy: it might stimulate uterine contractions and cause an abortion.
- When breast-feeding: it might pass into the breast milk. The effects of hibiscus in new born children is unknown.
- When trying to conceive: in some countries hibiscus has been used traditionally as a birth-control medicine.
- Within 2 weeks of scheduled surgery: hibiscus might make blood sugar control difficult during surgery.
- If you are taking any of the following medicines: diclofenac, chloroquinine, paracetamol (also known as acetominaphen), statins. Hibiscus might change the way the body absorbs, metabolises or eliminates these medicines, either making them less effective or increasing the strength of their action beyond what is required or safe. If you are taking medicines for high blood pressure or diabetes, use hibiscus under medical supervision: as hibiscus also acts on blood pressure and blood sugar, the dose of those medications may need to be adjusted.
[1] Easy Ayurveda. https://www.easyayurveda.com/2018/01/12/hibiscus-flower-leaves-uses/ Accessed 02/02/2022. [2] Me & Qi. https://www.meandqi.com/herb-database/roselle-flower-buds Accessed 02/02/2022. [3] Plants For a Future. https://pfaf.org/ Accessed 26/01/2022. [4] Plants For a Future. Hibiscus sinosyriacus - L.H.Bailey. https://pfaf.org/user/Plant.aspx?LatinName=Hibiscus+sinosyriacus Accessed 02/02/2022. [5] A Barefoot Doctor's Manual: The American Translation of the Official Chinese Paramedical Manual. Hu-Nan Chung, Yao Yen Chiu So (Authors), John E Fogarty International Center for Advanced Study in the Health Sciences (Translator). Running Press, 1977. [6] Choi Goya, Yoon Taesook, Choo Byungkil, Lee Aeyong, Chae Sunguk, Ju Youngsung, Kim Hokyoung (2007). Study on the Medicinal Parts and Expected Efficacys of the Hibiscus syriacus by Literature Review on the Classics of Oriental Medicine. Korean Journal of Oriental Medicine Vol. 13 Nº2 2007. [7] Hibiscus rosa-sinensis - L. https://pfaf.org/user/plant.aspx?latinname=Hibiscus+syriacus. Accessed 26/01/2022. [8] Hibiscus mosceutos - L. https://pfaf.org/user/Plant.aspx?LatinName=Hibiscus+moscheutos. Accessed 26/01/2022. [9] El Shazly J.M.N.M. (2019). A Pharmacognostical Study of Hibiscus syriacus L. Family Malvaceae. PhD thesis. Pharmacognosy Department, Faculty of Pharmacy, Cairo University. [10] Yu Ri kim, Sun Young Lee, So Min Lee, Insop Shim, Mi Young Lee (2022). Effect of Hibiscus syriacus Linnaeus extract and its active constituent, saponarin, in animal models of stress-induced sleep disturbances and pentobarbital-induced sleep. Biomedicine & Pharmacotherapy 146 (2022) 112301. [11] Kapoor M., Kaur G., Kaur N., Sharma C., Batra K., Singh D. (2021). The Traditional Uses, Phytochemistry and Pharmacology of Genus Hibiscus: A Review. European Journal of Medicinal Plants 32(4): 1-37, 2021; Article no.EJMP.68419.
Mediterranean Healing Herbs 