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Growing Oranges

Common name: Orange, sweet orange, bitter orange, Seville orange

Botanical name: Citrus sinensis (sweet orange), Citrus aurantium (bitter orange or Seville orange)

Origin: North-eastern India, parts of Myanmar (Burma) and China. Introduced into Europe between 200 and 300 A.D.

Among the world’s most popular fruits, oranges are well known for being as healthy as they are delicious. High in vitamin C, they are used for everything from marmalade to puddings and savoury dishes, and are also a delicious snack on their own.

Growing

Orange trees are compact, dense and evergreen, growing to little over 3m tall. White, sweetly scented blossoms in spring precede the fruit.

Plant the trees in full sun in deep, well-drained soils with moderately acidic to slightly alkaline pH levels. Extremely alkaline soils and brackish water are not favourable at all. Oranges require regular watering from flowering in early spring to early autumn, but don’t overwater as this can cause fruit to split. Fertilise with a 3:1:5 slow-release fertiliser at the recommended rate three times a year (in July, December and March) and apply 75g of magnesium sulphate (Epsom salts) per tree at the same time. Mulch with an organic material as far out as the drip line of the tree and be on the constant lookout for pests like citrus psylla, citrus swallowtail caterpillars, aphids, scale, mealybugs, thrips and red spider mites, as well as the fungal diseases black spot and sooty mould.

Propagation

Oranges are usually budded onto suitable rootstocks, but can also be grown from cuttings although this method is seldom used. Seedlings are not advisable as fruit can be of indifferent quality and trees take longer to bear fruit. In commercial farming vegetative reproduction is essential for good quality fruit.

Pollination

Oranges are self-pollinating. Crosspollination with other citrus species can sometimes induce heavier fruit set.

Suitable climates

Oranges grow best in the warmer parts of South Africa where rainfall is high or irrigation water is available. Extremely cold climates are not suitable for oranges. Subtropical climates close to the ocean are also not ideal growing conditions.

Cultivars or varieties

These are the major types of oranges:

Navels – These early ripening varieties produce large fruit with a prominent ‘navel’. The flesh is firm-textured with a strong, sweet flavour. The seedless fruit peels easily and segments separate without difficulty. Navels are not suitable for commercial juicing due to bitterness that develops after processing. Cultivars grown in South Africa include ‘Bahianinha’, ‘Palmer’ and ‘Washington’.

Valencias – These late-ripening varieties produce medium to large fruit with excellent flavour and abundant juice. The fruit, which hangs on the tree for extended periods, can be acidic if picked before fully ripe. It contains very few seeds or often no seeds at all. It is ideal for juicing and processing. Cultivars grown in South Africa include ‘Olinda’, ‘Midnight’, ‘Turkey’ and ‘Delta’.

Blood oranges – These oranges have pink or red flesh, the colour of which is more intensive in colder climates.

Bitter oranges – Juicy and extremely sour, these are generally used for marmalade.

Fruit uses

Oranges can be used fresh in desserts or savoury meals, or juiced, made into marmalade, preserves or as a flavouring in countless dishes. Some varieties have specific uses.

Ornamental value

These attractive plants can be used in the ornamental garden or grown successfully in large pots or containers. The heady fragrance of the flowers is a lovely added advantage of these multifaceted plants.

Interesting facts

The change of fruit colour from green to orange is brought about by cooler temperatures, and is not necessarily a sign that the fruit is ripe. Oranges can ripen and still be green coloured in climatic regions with constantly warm temperatures. Certain late-ripening cultivars can change from an orange colour back to green if warm temperatures prevail after winter and the fruit is still hanging on the tree.

Orange peels can attract slugs and snails away from your plants so that they can be collected and removed. Use piles of them on the soil.

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