Fruit & Vegetables Aussie Bush Tucker - An Introduction to Common Native Foods of Australia

Karkalla growing at the edge of the world, South Head, Sydney Harbour. © JPM, 2022.

Who can miss those bright pink flowers with prominent yellow stamens amidst a mat of tough, fleshy leaves? Welcome to the world of karkalla, one of Australia's tastiest native fruits!

Names

Commonly called karkalla in the southern parts Australia by the indigenous peoples, this resilient succulent creeper is otherwise known as pigface and sea fig because of the shape and flavour of their ripe fruits (Low, 1989: 57-59), although one source now lost to me suggested it may have come from an Afrikaans slang word for their version of the same plant, 'bigvys'. Also common in southern Africa and south America, Australia has at least four native species, three naturalised introduced species and two edible look-alikes. These plants have been classified as the genus Carpobrotus (C.), Greek for "edible fruits", although older literature such as Maiden and von Mueller may still refer to them by their older African taxon, Mesembryanthemum. Karkalla proper is C. rossii, found mostly in Victoria, South Australia and Tasmania; common pigface (C. glaucescens) in coastal NSW and Queensland; coastal pigface (C. virescens) in southern, coastal Western Australia; and inland pigface (C. modestus) can be found in arid, interior regions across WA, SA, NT and western NSW.

The two native look-alikes are Sarcozona praecox, an inland succulent with a somewhat more erect habit (Low, 1991: 30; Hansen & Horsfall, 2019: 302-303), and round-leaf pigface Disphyma crassifolium (round-leaf pigface), which has a much smaller, rounded plant profile overall, as detailed below (Low, 1991: 30; Hansen & Horsfall, 2019: 292-293). A South African interloper, the hottentot fig (C. edulis), also called ice plant in the USA and elsewhere (Deane, 2022) and a Chilean one, the sea fig (C. chilensis), round out the most common culprits to be discovered during foraging for these delicious fruits.

Habitat and Range

Karkalla is a coast- and salt-lover by nature; wherever you find sand and salinity you will be sure to find this hardy creeping succulent. Its range seems sparser the further north you travel from the Tropic of Capricorn, however you will find it abundantly in coastal regions south of Yeppoon in the east and Coral Bay in the west, including coastal Tasmania and the Great Australian Bight. Look for it at the coastal verge between the raging surf and the first line of trees. It is happy to clamber over seaside rocks, escarpments and pots and is a popular ornamental in gardens everywhere (such as my apartment common property). Karkalla has a deep root system, far more elaborate than their surface stems and branches, and can easily take over entire areas as the exclusive botanical inhabitant if conditions are favourable to its existence. The inland look-alike species may be found in arid regions across West and South Australia.

Figure 1. Distribution of Carpobrotus (all species) across the continent. Atlas of Living Australia.


Figure 2. Distribution of Sarcozona (all species) across the continent. Atlas of Living Australia.


Figure 3. Distribution of Disphyma (all species) across the continent. Atlas of Living Australia.


Identification

Key Identifying Features

• Thick, succulent, triangular leaves, 5-12 cm in length, usually green with a pink or red tinge (desert species may be greyish- or purple-tinged and wrinkly)
• Leaves grow oppositely, two per node
• Subsequent leaf nodes are angled at 90° to the previous node
• Stems form sprawling, ground-covering mats
• Stem and leaf sap is clear or inconspicuous
• Pink-petaled flowers 5-12 cm in diameter with a white or yellow throat, dozens to hundreds of tiny yellow anthers and an 'octopus legs' stigma in the centre.
• Fruit has two to four triangular horned lobes on the top
• Fruit may still have dried flower parts attached
• Fruit turns red or yellow when fully ripe
• Fruit flesh resembles green kiwifruit dotted with tiny brown-black seeds
• Fruit emits a pleasant, fragrant scent after picking

Besides its unique habitat usually on the coastal verge, especially just behind dunes, but also in desert sands, karkalla is easily identified for its triangular, fleshy leaves, sprawling mass of creeping stems, and usually bright pink, sometimes red, orange, yellow or white, flowers with bright yellow or white stamens in the centre.

Figure 4. Karkalla (C. rossii) foliage. Note the triangular shape, fleshy texture and occasional red tinge. Great Ocean Road, VIC. © JPM, 2022.


Figure 5. Common pigface (C. glaucescens) foliage. South Head, Sydney Harbour. © JPM, 2022.

Figure 6. Desert pigface foliage (S. praecox). When pigface lacks water the foliage will wrinkle, a common feature in the desert species. Atlas of Living Australia. © I. Dudley, 2022.


Figure 7. Distinctly stubby, rounded foliage of the aptly-named round-leaf pigface (D. crassifolium). Rottnest Island, WA. © JPM, 2023.


Flowers appear in early spring (Aug-Sep, later further south, often with a second flowering in Jan-Mar), often as an impressive display of bright pink with the golden centres and attract copious numbers of bees and other pollinators. Most species' flowers are a light or dark pink, while others can be yellow-white, usually with a lighter white or yellow 'throat' towards the centre of the flower.

Figure 8. Pink-purple flowers of common pigface (C. glaucescens). The other native species (C. rossii; C. modestus and C. virescens) flowers are virtually identical. South Head, Sydney Harbour. © JPM, 2022.


Figure 9. Yellow-white flowers of the non-native hottentot fig (C. edulis). Note the hundreds of anthers and 'octopus legs' pistil, centre. Atlas of Living Australia. © A. Bonnitcha, 2014.


Figure 10. Round-leaf pigface (D. crassifolium) putting on a show! Note the more prominent white throats. These flowers are also smaller than Carpobrotus species. Atlas of Living Australia. © R. Lawrenz, 2008.


Pollinated flowers wither into a soft green fruit with two to four leaf-like lobes, giving pigface its English name (I don't see the resemblance, personally). The fruits will take two or three months to fully ripen, and many species will change colour when the fruit is ready to be picked, ranging from green with pink edges or blushing, to yellow, to a vibrant red. Many ornamental species have been bred for their flowers, sometimes resulting in fruits that do not change colour very much. In this case, look for the withered flower heads as markers of the fruit, as well as withering at the fruit stem indicating it is ripe, or possibly past ripeness.

Figure 11. Unripe fruit of common pigface (C. glaucescens). Note the green colour and dried flower petals in the centre. Sydney Olympic Park. © JPM, 2021.


Figure 12. Ripe fruit of common pigface (C. glaucescens) turn pinkish-red and wither slightly. Unripe fruit, centre, are green, displaying their distinctive fleshy horns. Fruits of the other native species (C. rossii; C. modestus and C. virescens) look virtually identical but may be brighter red in colour. Mt. Annan Botanical Garden. © JPM, 2023.


Figure 13. Karkalla (C. rossii) ready to pick. Boyd's Tower, Edrom, NSW. © JPM, 2023.


Figure 14. Ripe fruit of the South African hottentot fig (C. edulis) exhibiting the distinctive lobes and yellow pigmentation. Wikimedia Commons. © Llez, 2006.


Figure 15. Ripe fruits of round-leaf pigface (D. crassifolium). The fruits of this species are very small, often less than 1 cm, and usually not worth harvesting. Atlas of Living Australia. © Mike, 2019.

Culinary Uses

Karkalla fruits are absolutely delicious, tasting somewhat like gooey, salty figs. Ripe fruit will snap straight off near the base when pulled and immediately emit a pleasant, fruity aroma. Peel the fruit across the belly near the lower stem and then squeeze or suck out the sweet, salty, sticky and seedy interior. Alternatively, grasp the fruit by the horns and squeeze out towards the other end; the flesh and juice will pop right out into your mouth! They are best eaten fresh, but can be dried and reconstituted. Add them to smoothies, jams, jellies, icecream or anything else that would enjoy a surprising, salty, fruity fig flavour, such as a cheeseboard or green salad. Avoid fruit specimens that are exceedingly wrinkly, smelly, rotten, fermenting or otherwise damaged.

Williams (2010 I: 21) assigns the following nutritional information:

the fruit contains good amounts of sodium (around 231mg/100g), potassium (207mg/100g), calcium (173mg/100g) and magnesium (95mg/100g) – with small amounts of iron, zinc, and copper.

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Figure 16. Pluck ripe fruits near the stem and they will snap right off into your hand and emit a pleasant, fruity aroma (C. glaucescens, pictured). Mt. Annan Botanical Garden. © JPM, 2023.

Figure 17. Squeeze the fruit from the 'horn' end straight into your mouth and enjoy! Mt. Annan Botanical Garden. © JPM, 2023.

Figure 18. Freshly harvested karkalla (C. rossii) growing abundantly at Cocora Beach, Eden, NSW. © JPM, 2023.

Figure 19. What to expect inside karkalla (C. rossii). Boyd's Tower, Edrom, NSW. © JPM, 2023.

Figure 20. Freshly harvested and peeled fruit of common pigface (C. glaucescens) resembling kiwifruit, found wild on South Head, Sydney Harbour. © JPM, 2021.

The leaves of all the above-mentioned plants can also be eaten as a textured, salty green, especially the smaller round-leaved pigface (D. crassifolium). Leaves are best cooked at high temperature, either boiled or grilled in stir fries, or on a BBQ with meat, the traditional indigenous method of preparation. In my experience, the leaves and the outer skins of the fruits have a tendency to be astringent and unpalatable raw (and extremely salty!), but some individual plants are more pleasant than others.

The best specimens I have harvested so far were growing happily, and unmolested until I found them, on a rocky area near Sandy Bay beach in Hobart, Tasmania. Most of the locals had no idea they were a native Aussie bush food and perfectly safe to eat (the specimens near the Hawk Neck penguin rookery, Tasmania, were also delicious). Your trip to the beach should never be complete without checking whether the native karkallas, growing abundantly behind the surf Australia wide, are in full bloom or full fruit!

Medicinal Uses

Hansen & Horsfall (2016: 52-53; 2019: 105) list multiple traditional cures made from coastal pigfaces (in WA, C. virescens and C. rossii). Crushed leaf infusions (teas) were used for diarrhoea, dysentry, and stomach cramps, as well as a mouthwash/gargle for sore throat and other mouth infections. Crushed leaf juice can be applied externally akin to Aloe vera juice to relieve burns, bites, stings, sunburn and fungal skin infections.

Duke (2002: 393) lists nine medicinal properties of the South African invasive, C. edulis, properties which are undoubtedly compatible to the Australian natives: antibacterial; antiseptic; antiviral; astringent; diuretic; fungicide; hemostat; laxative; and a vasoconstrictor. One of his sources is more detailed in preparations (Hutchings et al.,1996: 93; Van Wyk et al., 1st ed. 1997: 70-71 [2nd ed. 2009: 78-79] is also cited as a source but this book is not available to me):

Juice from pounded leaves is used as a gargle for sore throats, diphtheria and thrust and to treat digestive troubles, diarrhoea and dysentery ... . Also applied to ringworm, severe weeping infantile eczema, burns and scalds, and applied diluted to the mouth for sprue [celiac disease]. Fruit infusions are taken by Khoi women during pregnancy to ensure an easy birth and leaf sap is smeared over the head of a new-born child to make it nimble and strong.

Leaf sap is effective against blue-bottle stings when applied directly. Sap from the plant is mildly antiseptic and syrup made from the fruit is said to have laxative properties.

Mixtures of dried leaves and stems yield catechol tannins. These readily form phlobaphenes during the preparation of aqueous and alcoholic extracts of the plant. Malic and citric acids and their calcium salts are present in the sap. The presence of mesembrine is reported but not confirmed. Red-violet betalains and leucoanthcyanidins have been isolated. Juice from stems and leaves is used in patented drugs and pesticides.

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The laxative effects were certainly well known to early colonial-era explorers of Australia's barren inland region, as astutely recorded in the journal of one E. M. Curr during his 1840s wanderings of central Victoria: "On this trip it was exceedingly hot during the day, though not at night, and the pig's-faces were covered with ripe fruit, so, naturally, as we had been living on mutton and damper for months, we indulged in them rather more than we should have done, and suffered in consequence a smart indisposition for a few hours" (cited in Low, 1989: 58).

Williams (2010 I: 21) is very helpful with her additions to the above:

An old remedy for tuberculosis mixed the leaf juice [of South African C. edulis] with water, honey and olive oil. Doubtless the Australian plants gained a similar therapeutic reputation. The mucilaginous leaf juice was popular as a healing agent. In Australia it was found to be particularly efficacious for soothing irritable midge bites and marine stinger injuries. The latter, which can be extremely painful, are sometimes life threatening. The anti-irritant properties of the plant are interesting, as various plants in the family (including the genus Carpobrotus) contain mesembrine. This alkaloid has mild anaesthetic effects and is chemically related to cocaine.

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Maiden (1889: 194) also noted similarly that pigface was "...used in South Africa. There the expressed juice of the succulent leaves taken internally checks dysentery, and acts as a mild diuretic, while it is also, for its antiseptic property, used as an excellent gargle in malignant sore throat, violent salivation, and aphthae [mouth and throat ulcers], or in the form of a lotion in burns and scalds."

Overall, it is a very useful medicinal plant in addition to its edibility profile and one easily attained across much of Australia's landmass. That its mashed leaves and juice can be used to ease jellyfish stings and horsefly/mosquito bites in the absence of vinegar is worth knowing by every beach-loving Australian.

Other Uses

Williams (2010 I: 21) makes note of the cellular gums of Carpobrotus and other related plant taxa (e.g. Mesembryanthemum and Aptenia) for their potential industrial use as:

emulsifying, gelling, adhesive, lubrication, binding or coating agents. They have diverse applications for food processing and packaging – as well as in the pharmaceutical, veterinary, personal care and cosmetic industries. These gums are also suited for manufacturing many products of industrial importance: paper, adhesives, inks, textiles, paints, ceramics, explosives, various types of cleaning products (including detergents), fire-fighting agents, agricultural chemicals (including pesticides and fungicides) – as well as in oil and gas production. In addition, they can be used in photographic and lithographic processes.

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The exact formulations for such uses are the properties of several patents which may or may not be expired.

Caution!

All species of Carpobrotus are extremely high in oxalic acid (approximately 12% fresh weight; Williams 2010 I: 21), especially the leaves and fruit skins. Raw consumption of the leaves of this plant should be sparing. Cooking at high temperatures, e.g. stir fry, oven or open flame roasting/grilling, or boiling, is the safest way to denature these potentially toxic substances.

References/Further Reading

Atlas of Living Australia, "Carpobrotus edulis." [LINK]
Atlas of Living Australia, "Carpobrotus glaucescens." [LINK]
Atlas of Living Australia, "Carpobrotus modestus." [LINK]
Atlas of Living Australia, "Carpobrotus virescens." [LINK]
Atlas of Living Australia, “Carpobrotus rossii.” [LINK]
Atlas of Living Australia, "Disphyma crassifolium." [LINK]
Atlas of Living Australia, "Sarcozona praecox." [LINK]
Deane, Green (2022), "Newsletter #493." [LINK]
Duke, James (2020), Handbook of Medicinal Herbs (2nd ed.; Boca Raton: CRC Press), p. 393.
Hansen & Horsfall (2016), Noongar Bush Medicine, pp. 52-53.
Hansen & Horsfall (2019), Noongar Bush Tucker, pp. 104-105 (C. rossii & C. virescens); pp. 182-183 (C. modestus); pp. 292-293 (D. crassifolium); pp. 302-303 (S. praecox).
Hiddins (2002), "Pigface (Carpobrotus sp.)." [LINK]
Hutchings, Anne, et al. (1996), Zulu Medicinal Plants: An Inventory. Pietermaritzburg: University of Natal Press, p. 93. [LINK]
Low (1989), Bush Tucker, pp. 57-59.
Low, (1991), Wild Food, p. 30.
Maiden (1889), Useful Native Plants, pp. 44 & 194.
Van Wyk, Ben-Erik, Bosch Van Oudtshoorn and Nigel Gerike (2009), Medicinal Plants of South Africa. 2nd. Edition; Pretoria: Briza Publications, pp. 78-79.
Williams, Medicinal Plants, Vol. I, pp. 20-22.