Grapefruit - Citrus x paradisi Star Ruby

The Star Ruby grapefruit, in Latin Citrus x paradisi, is a variety of grapefruit cultivated on a large scale: it is the one most often sold in supermarkets. It is a very productive variety, appreciated for its very pink, almost seedless, juicy flesh with a fragrant, tangy and slightly sweet taste, and a low bitterness. This citrus forms a beautiful bush, which can exceed 6 metres (20 feet) high in open ground, and produces large white and waxy flowers in spring, with a sweet fragrance. Everything is big with this citrus, from the leaves to the yellow fruits, tinged with deep pink, which can exceed 12cm (5in) in diameter. It can be used to make refreshing fruits and superb vitamin-packed fruit salads, even in winter. It is not very hardy and perishes below -7°C (19.4°F). It should be grown in a large container to store in a greenhouse over winter, or in open ground in warm regions spared from heavy frosts.

Citrus x paradisi, Grapefruit in English, has clusters of fruits borne inside the branches. It is probably native to the Caribbean, where its parents Citrus maxima and Citrus sinensis, the orange tree, hybridised. 'Star Ruby' is a famous North American cultivar. It is a large bush of the Rutaceae family. Its habit is naturally rounded. This beautiful tree reaches a height of  6 m and spreads over about 3m (10ft) in open ground if the growing conditions are favourable. Its growth will of course be more limited in a pot. Its young branches are hairy, then become smooth over time. Citrus paradisi Star Ruby flowers abundantly in March-April. It produces large flowers for a Citrus. They are white, star-shaped, divinely fragrant, and gathered in clusters. They give way to round fruits, with a diameter ranging from 10 to 12cm (4 to 5in). Their thick skin is green at first, then yellow and finally pinkish when ripe in hot climates and has a smooth appearance. The translucent pink-red flesh of the fruit is at the same time slightly sweet, tangy, bitter and flavourful. The fruits are harvested in spring in our climates. The large evergreen leaves of this citrus, which are leathery and aromatic, often have a petiole with a small wing.

The Star Ruby grapefruit is consumed fresh or as an appetiser, in desserts and of course as juice. This remarkably juicy fruit has a unique flavour, a subtle blend of acidic, sweet, bitter and fragrant notes. It is also a very beautiful ornamental bush in very mild climates. It is particularly decorative with its superb deep green and shiny foliage, its clusters of large pink fruits and its naturally balanced shape.

Like all  Citrus,  Citrus x paradisi contains in its leaves, flowers and fruits pockets of essential oil often visible to the naked eye, from which essential oil with antiseptic, tonic and appetising properties is extracted by distillation (flowers and leaves) or by pressing (zest). The fragrance of the essential oil is described as fruity, tangy and slightly bitter, with floral notes.

Most citrus trees thrive in open ground in Mediterranean coastal regions where they find the year-round heat they need. But to fruit well, they must not lack water or nutrients. It is a self-fertile bush, which means that a single bush is sufficient for pollination and fruiting.