Calamondin - Citrus madurensis

The Calamondin, Citrus madurensis or Citrus mitis in Latin, also known as the indoor orange tree due to its small stature, the appearance of its fruits, and its better tolerance to indoor atmospheres. It is appreciated for its ornamental qualities, as well as the subtly fruity and tangy flavour of its fruits, which work wonders in the kitchen. It blooms and bears fruit all year round, more abundantly in spring, so its small mandarins, green, yellow or orange when ripe, and white flowers with a sweet fragrance coexist permanently on the bush. It is not very hardy and needs to be stored indoors during winter outside of very mild regions. Easy to grow in a pot and relatively tolerant of indoor cultivation, in a bright, cool, and ventilated room, it will spend the summer on a sunny terrace.

The Citrus madurensis is a bushy plant from the Rutaceae family native to Southeast Asia. It is a hybrid of kumquat (Fortunella margarita) and mandarin (Citrus reticulata), with a rounded habit, reaching a height of 2 or 3 metres (7 or 10 feet). Not very hardy, it can be planted in the ground in the narrow coastal areas of the Mediterranean. Elsewhere, it will be grown in a pot and stored indoors at the first signs of cold weather. The Calamondin blooms and bears fruit all year round. It produces small white flowers with a characteristic sweet fragrance reminiscent of orange blossoms, which give way to small round fruits, measuring 2 to 4cm (1 to 2in) in diameter. They are harvested when ripe, usually from January to March, when they have turned a beautiful bright orange colour. The moderately thick skin has a sweet flavour and a subtle aroma of bitter orange. The juicy, bitter, and tangy pulp contains numerous seeds. Overall, their flavour is reminiscent of bitter orange but more floral and aromatic. The evergreen leaves are small, rounded, and shiny dark green. Like all Citrus plants, the Calamondin contains essential oil glands in its leaves, flowers, and fruits, which can be extracted by distillation (flowers and leaves) or by pressing (zest).

The Calamondin is the ultimate indoor citrus tree, which is why it is also known as the indoor orange tree. Very different from orange trees, it is the only citrus tree capable of withstanding the dry atmosphere of our heated indoor spaces in winter. However, it is important to provide it with enough water to keep the soil consistently moist, without excess, and regularly mist the leaves. This will also help prevent red spider mite infestations. The fruits and leaves are part of the culinary traditions of several Southeast Asian countries. The fruit is used in both savoury and sweet dishes, as well as for making delicious jams. Its subtle flavour pairs well with savoury dishes like tagines or the famous duck à l'orange.

Most citrus trees thrive in the ground in coastal Mediterranean regions where they can enjoy the necessary year-round warmth. Not very hardy, the Calamondin starts to suffer from cold temperatures below -2°C (28.4°F) and cannot withstand temperatures below -6°C (21.2°F). It is a self-fertile bush, which means that a single plant is sufficient for complete pollination and fruiting. However, if your citrus tree remains indoors permanently, you will need to occasionally allow pollinators to do their work or, if you have the delicate touch, perform hand pollination with a brush.