Citrus hystrix - Kaffir Lime

Citrus hystrix, known as Combawa, is an ancient citrus tree, not widely known in the world, but highly appreciated in cooking and perfumery for the zest of its fruits as well as its highly aromatic leaves. This small tree with moderate growth is very fruitful. Its abundant spring flowering takes the form of small pleasantly scented star-shaped flowers, ranging from white to pink. They are followed by the formation of pear-shaped fruits with a greenish skin that appears dented. Not very hardy, it perishes below -4° C (24.8° F). It can be cultivated in a large container to be stored in a greenhouse during winter, or in open ground in warm regions that are spared from severe frosts.

Citrus hystrix is also known as the prickly lime, wild lime, Makrut lime, kaffir, Reunion Island lime, or Papeda from Mauritius depending on the region. It is a large, more or less spiny bush from the Rutaceae family, with a rather erect bushy habit. It originates from the Sunda Islands in Southeast Asia. It is a citrus tree belonging to the Papeda group, which is ancient from a botanical point of view. It is mainly distributed in New Caledonia and often cultivated in Creole gardens on the island of Reunion where it is particularly appreciated. This small tree reaches a height of 3 m (9.8 ft) and spreads over about 2 m (6.6 ft). Not very hardy, it can only be planted in open ground in the warmest regions. Elsewhere, grow in a pot and store it at the first signs of cold weather. Cultivated for its leaves and fruits, Combawa flowers abundantly in March-April, and then again, more sporadically, in September. It produces pink buds that open into small white flowers with a sweet and delicious fragrance of neroli, characteristic of Citrus. They give way to pear-shaped fruits, tapering at the top and rounded at the base. They measure about 6 cm (2.4 in) in diameter. Their thick lime green skin has a strongly lumpy appearance. The fruit pulp, white-green and translucent, is both very acidic and bitter. The fruits are harvested in September-October, while still green, when their concentration of essential oils is at its peak. The persistent and aromatic leaves of this citrus tree have a characteristic petiole, with a very wide wing, sometimes larger than the leaf blade itself. They have a pungent, strongly spicy flavour.

The fruits and leaves are part of the culinary traditions of several Southeast Asian countries. Combawa is used in cooking to enhance exotic or Creole dishes. The leaves, rolled up and then cut into thin strips, are added to the dish at the beginning, then in the middle, and finally towards the end of cooking. It adds a very subtle touch of lemongrass to dishes like tomato rougail. The zest is sometimes used. Its juice is used in refreshing drinks, to which it adds a touch of bitterness.

Like all Citrus trees, Combawa contains visible essential oil glands in its leaves, flowers, and fruits, that can be extracted by distillation (flowers and leaves) or by pressing (zest). The essential oil has anti-inflammatory and anti-rheumatic properties, as well as sedative properties, helping to fight against stress and insomnia. The fragrance of the essential oil is described as fresh, citrusy, acidic, with green notes.

To bear fruit well, they must not lack water or nutrients. Not very hardy, it starts to suffer from cold temperatures below -3° C (26.6° F). It is a self-fertile bush which means that a single individual is sufficient for complete pollination and fruit set.