Citrus hystrix

Evergreen shrub growing 6 m tall by 3 m wide at a medium rate. Hardy to UK zone 10. Flowers are small, fragrant, four to five-petalled and white, pollinated by insects. Self-fertile. Tolerates light sandy, medium loamy, and heavy clay soils with good drainage. Grows in mildly acidic, neutral, and mildly alkaline soils. Requires full sun and prefers moist conditions.

Description

A low shrubby tree up to 6 or 8 m high. The trunk is thin and crooked. It has slender sharp thorns. The leaf petiole has very large lobes. The leaf is oval. The leaves can be 8-15 cm long by 3-5 cm wide including the leafy stalks. The leaves are dark green and shiny above and pale and matt underneath. The flowers are small and white. The fruit are small (8 cm across) with a rough, thick skin and very little edible pulp inside. They are very acid. The peel of the fruit is very fragrant.

Edible Uses

Kaffir lime leaves are used as a flavouring and to make teas. They have a distinct lime flavour and can be finely sliced and added raw to salads or incorporated into cooked dishes, lending a pleasant citrus note to soups, curries, rice, stir-fries, fish cakes, and marinades. Leaves can be sourced from homegrown plants or bought fresh or dried at Asian or specialty grocers. The fruit is edible raw; it is rough-skinned with a bitter flavour and 5–7cm in diameter. It produces only a small amount of juice, but this is very powerful and can be added to other fruit juices to make them taste more vibrant. The fruit is also used to make preserves. The rind is used as a flavouring in cooked foods, and can be candied or dried for use in curry pastes. The four-to-five-petalled white flowers are fragrant and edible.

Traditional Uses

The leaves and fruit are used to make drinks or to flavour food. They are added to soups and curries. The leaves are pounded into a jelly and mixed with hot chili pastes. The fruit are eaten crystallised. The juice of the fruit is used for flavouring. The lemon scented fruit are eaten with fish.

Medicinal Uses

The fruit is used medicinally, primarily as an insecticide for washing the hair and treating the feet to kill land leeches. Citrus species are rich in vitamin C, flavonoids, acids, and volatile oils, and research into their active ingredients is ongoing. They also contain coumarins such as bergapten, which sensitizes the skin to sunlight; bergapten is sometimes added to tanning preparations to promote pigmentation, though it can cause dermatitis or allergic reactions in some people. More recent applications include use as sources of antioxidants and chemical exfoliants in specialized cosmetics.

Distribution

A tropical plant. It mainly occurs in lowland areas in the tropics. It suits hardiness zones 10-12. In Yunnan.

Where It Grows

Africa, Asia, Australia, Brazil, Cambodia, China, Cuba, East Africa, East Timor, Europe, Fiji, France, Hawaii, India, Indochina, Indonesia, Japan, Laos, Madagascar, Malaysia, Mauritius, Mediterranean, Middle East, Morocco, Myanmar, North Africa, Northeastern India, Pacific, Papua New Guinea, PNG, Philippines, Samoa, Saudi Arabia, SE Asia, South America, Spain, Sri Lanka, Tasmania, Thailand, Timor-Leste, USA, Vanuatu, Vietnam, West Indies,

Cultivation

Kaffir lime is a thorny, multi-stemmed, evergreen shrub or small tree. Three main climates are suitable for commercial citrus production - tropical climates, subtropical with winter rain in the Mediterranean and semitropical with summer rainfall in Florida and southern Brazil. Kaffir lime grows well in sandy, well-drained soils in full sun to light shade. Deep, fertile soils generally produce the best fruit crops. Best overall performance occurs in full sun in locations sheltered from strong winds. The optimal temperatures for citrus cultivation range between 25 - 30°c, with the coldest month having an average minimum of at least 15°c. Growth generally ceases below 13°c and above 38°c. If there are dry periods of more than three months, then irrigation will be necessary. Kaffir lime can tolerate occasional, short-lived frosts. An easily grown plant preferring deep, well-drained but moisture-retentive loamy soil in full sun. Kaffir lime prefers a pH in the range of 5 - 6. Self Pollinating. Suitable for pots. Can be pruned to 2m.

Propagation

Sow fresh seed in containers as soon as ripe after thoroughly rinsing. Sow stored seed in containers as soon as possible. Germination usually takes place within 2–3 weeks at 13°C. Seedlings are prone to damping off and must be watered carefully and kept well ventilated. Seed is usually polyembryonic — two or more seedlings arise from each seed, genetically identical to the parent and typically free of any virus present in the parent. Prick out into individual pots when large enough to handle, and grow on until at least 10cm tall before planting into permanent positions. Half-ripe cuttings can be taken in July–August in a frame; this species roots easily from cuttings. Layering is also an option.

Other Uses

Extracts from the skin and juice act as an insecticide for washing the hair and treating the feet to kill land leeches. The fruits are rich in saponins, lather freely in water, and are used in hair shampoos and for washing clothes. In Cambodia, lustral water mixed with slices of the fruit is used in religious ceremonies. The fragrant leaves also contain saponins and serve as a hair wash. Two distinct essential oils are obtained — one from the leaves, another from the fruit peel — and kaffir lime oil is used in the pharmaceutical, agronomic, food, sanitary, cosmetic, and perfume industries, as well as extensively in aromatherapy.

Production

The tree flowers throughout the year but has most ripe fruit about June and July.

Other Information

A citrus of only minor importance in Papua New Guinea, but cultivated is some coastal areas.

Notes

There are 20 Citrus species. Several hybrids have been formed. It contains alpha-tocopherol (Vitamin E) content of 66.00 mg per 100 g.

Nutrition

Synonyms

Also Known As

Bai magrood, Caffre lime, Fatt-fung-kam, Ichang lime, Jeruk purut, Jeruk sambal, Kabuyau, Kahpiri dehi, Karokaro, Kolobot, Khatta nabbu, Krauch soeuch, Kro'ch sae'ch, Kudala-dehi, Kulubot, La chanh, Leech lime, Lemon titi'u, Limau purut, Mahkroot, Ma kruut, Makrut, Mauritius papeda, Odu dehi, Papeda, Shauk-cho, Shauk-nu, Shauk-waing, Shouk-pote, Soco ni vavalagi, Soh-kyniet, Som makrut, Swangi, Te remem, Voangabe

References (60)

• AAK, 1980, Bertanam Pohon Buah-buahan. Penerbitan Yayasan Kanisius, Jogyakarta. p 38
• Ambasta, S.P. (Ed.), 2000, The Useful Plants of India. CSIR India. p 128
• Anderson, E. F., 1993, Plants and people of the Golden Triangle. Dioscorides Press. p 206
• Arora, R. K., 2014, Diversity in Underutilized Plant Species - An Asia-Pacific Perspective. Bioversity International. p 62 (As Citrus combara)
• Ashton, M. S., et al 1997, A Field Guide to the Common Trees and Shrubs of Sri Lanka. WHT Publications Ltd. pdf p 345

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