Bitter oranges

For me, oranges are an apt festive topic as I always received one in my childhood Christmas stocking. Although I’ve never been big on the fruit’s flesh, I have always loved the colour and shine of the skin, as well as the fruit’s scent. And now I have an orange tree in my garden I love the perfumed blossom season as well.

During my visit to Iran earlier this year I noticed a small tree used extensively in the gardens – primarily lining the avenues alongside the long, narrow rectangular pools. At the time we were told it was “a kind of citrus” and further investigation reveals it to be Citrus x aurantium.

But the fruit is sour or bitter, although all citrus were bitter originally. Native to southeast Asia, the trees moved along the trade routes and there is clear written evidence that bitter orange preserves were being made in Persia by about 1300.

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Citrus x aurantium. Photo: A Barra

Tim Entwisle, director of the Royal Botanic Gardens in Melbourne, blogged about the fruit in September this year, saying: This is a hybrid between a pomelo (a large grapefruit-like fruit) and a mandarin … Within this hybrid group are both bitter and sweet oranges. Those at the bitter end have more of the pomelo (C. maxima), and those at the sweet end, more mandarin (C. reticulata) and sometimes called Citrus x sinensis. Read the full post here.

Known as ‘narenj’ in Iran (very close to the Spanish word ‘naranja’), the fruit can be used as a substitute for lemons and limes (salad dressings) and are often paired with fish and rice dishes, to marinate chicken and for pickles.

Sugar was known very early in Persia, having been encountered in about 500BC in India by the soldiers of Darius I, and by those of Alexander the Great (who invaded Persia) in about 300BC. Anne Wilson, in The Book of Marmalade, postulates that “the Persians may have been the first people to have employed sugar as a foodstuff” (as opposed to a medicine). Read more about Scottish marmalade here.

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Sour orange trees flank a pool (empty) at the Eram Garden in  Shiraz, Iran. Photo: Sandra Simpson

The bitter orange tree has long been used in many ways. In Chinese herbal medicine, for instance, preparations made from leaves and fruit rinds were used to treat intestinal problems, including constipation, while in the West the flowers are still used to produce essences for aromatherapy.

Moorish poets from North Africa lauded the tree’s fruit and its blossom during Spain’s Islamic history (711-1492) and this orange has been cultivated around Seville since the end of the 12th century and, yes, this is the orange used in the famous marmalade (read more here) while the flowers are used to make orange-flower water. Bitter oranges – terrible for eating (as I can attest after whipping one from a tree in Seville and trying it) – have a higher pectin content than sweet oranges so are perfect for marmalade.

Another sour orange, Bergamot (Citrus bergamia, which confusingly turns yellow when ripe), is primarily grown for its essential oil which is used in natural medicines and perfumes and to flavour Earl Gray and Lady Gray teas. According to legend, Christopher Columbus introduced this tree to Italy from either the Canary Islands or the West Indies. While many believe the common name is linked to the Italian city of Bergamo in Lombardy, Pierre Laszlo in his 2008 book Citrus: A history, reckons it derives from a Turkish word, ‘beg-armudi’, which means ‘lord’s pear’ and adds that the French word ‘bergamotte’ was first used in 1536 for a variety of pear, before being applied to a citrus variety in 1699.

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The lovely Narenjestan Garden (or The Orangery) in Shiraz. The trees lining either side of the walkway are bitter oranges. Photo: Sandra Simpson

Sir Walter Raleigh took sour orange seeds to England; they were planted in Surrey and the trees began bearing regular crops in 1595, but were unfortunately (or predictably) killed by cold in 1739.

For 500 years, the bitter orange was the only orange known in Europe and was the first orange to reach the New World, being naturalised in Mexico in the mid-16th century.

But in the first half of the 17th century, sweet orange trees arrived in Portugal by ship and these quickly superseded the bitter ones.

Yet another bitter orange, the deciduous Poncirus trifoliata (or Citrus trifoliata) which is  native to China and Korea and sometimes called the Chinese or Japanese bitter orange, has been one of New Zealand’s favourite citrus rootstock trees for decades.

One nurseryman told me that it can stand 3°C more cold than any other rootstock, and it seems to help produce high-quality fruit that don’t dry out – but it is thorny.

Tree of the moment: Gordonia axillaris

Gordonia axillaris has the common name fried egg tree – and it’s not hard to see why, especially as the flat, white flowers with their generous yellow centres don’t die on the tree, but fall and land face up on the ground beneath. As you might guess from the flowers, camellias are closely related. Almost the nicest thing about this tree, for me, is that it flowers in winter – plus the evergreen leaves develop red tips in the colder seasons.

Photo: Sandra Simpson

Native to southern China, G. axillaris grows to about 3-5m high and wide. It can be pruned to promote bushiness. The genus is named for James Gordon, an 18th-century London nurseryman; while some of the flowers grow in the leaf axils, hence the species name, axillaris.

The Burke’s Backyard website (Australia) recommends planting in full sun to part shade in well-drained, slightly acidic soil. Fertilise in spring with azalea and camellia food or any all-round fertiliser.

Photo: Sandra Simpson

There are about 40 species in the Gordonia family, with only two not native to Asia.

A cousin to Gordonia, the deciduous US native Franklinia alatamaha (Franklin tree, named for Benjamin Franklin) has been extinct in the wild since 1803 – the only member of that family. Melbourne’s Royal Botanic Gardens has one specimen growing on in its nursery. Read more about the Franklin tree here by the always-entertaining Tim Entwisle.