Citrus: sweet and sour by Malcolm W. Campbell BA, MAIH, MIPPS.

The orange is what instantly springs to mind when we think of citrus, but in my experience, when a home gardener plants citrus it's an orange and a lemon and at least one other, either a grapefruit or a mandarin. While we eat far more oranges than lemons, the lemon seems to out feature the orange in the home garden, probably because even if you only plant one variety, they will usually bear fruit all year. While you can supply yourself with oranges all year round, you will probably need at least three varieties, each on their own rootstocks. You cannot deny that the orange and lemon are home garden legends, right up there with 'who-grows-the-best-tomatoes'. There could well be more oranges in cultivation in our home gardens and farm orchards than in the commercial production areas of Australia. Australians certainly grow more back yard citrus than any other nation, from my observations. I was fascinated in biology classes, by the cell structure of the orange flesh, which apparently has the largest cell structure in the plant kingdom. But why? It defies the cell theory of my teachers. Cells have to be small. Anyhow it's because of that huge tear-shaped delicious cell, that extracting their juice is so simple and why they are so popular commercially and in the fridge. There's probably no other beverage so universally drunk, except maybe water! It can be found in the soft drink cabinet, just about everywhere. I've even seen it on the pavements in tetrapacks in the markets in Kabul.

The sweet oranges that we all favour are selections and hybrids of the Citrus sinensis species, that must have come to us from China via the Silk Road with very early traders. Citrus oils are mentioned as being used in medicines in the Vedic period in India, about three millennia ago. I think it was the French 'Sun King', Louis XIV with his lavish orangeries in Versailles from about 1700, that did more to popularise the orange and orange cultivation, than any prior to him. While his elaborate glass structures for growing the treasured orange, would not be replicated by other than a few doting nobles in England, they made the fruit highly desirable in the best of circles. So much so, that the Bourbon and Spanish monarchs planted citrus orchards quite widely in the more suited regions of Mediterranean Spain, Portugal and the Italian Kingdoms, for the table and for ships' stores.

The importation of the citrus into Australia is generally accredited to Governor Phillip's Chaplain, the Reverend Richard Johnson, who brought plants and seeds of orange, lemon and limes from Rio de Janeiro while en route with the first fleet in 1788. The Riverland region on the River Murray in South Australia became the first extensively irrigated area under citrus cultivation from 1887 and today oranges and many other fine citrus are grown commercially in all mainland states and the Northern Territory.

I've never understood why the various citrus marketing authorities around Australia, market all navel oranges as 'Navels', when in fact there are quite a few varieties that make up that appellation. The potato marketing folk discovered the folly of selling generic spuds and their turn-about over the past year or two has seen a proliferation of named cultivars being marketed with much great consumer acceptance.

Even amongst the various 'Navel' orange cultivars there are quite a few degrees of sweetness and certainly different morphology or structure. They peel differently and the taste varies enormously according to season, variety, climate of their cultivation, as well as the state of maturity at harvest. I reckon the imported Californian 'Navel' tastes different to the local Sunraysia and Riverland 'Navels' and since they are probably different selections of 'Navel', that's not surprising. These are the reasons why so many home gardeners choose to grow their own. A 'Washington Navel' picked fresh and juiced for breakfast first thing in the morning before the winter sun has kissed it, is one of Australia's great taste sensations.

'Washington Navel' is without doubt the most popular home grown orange in Australia, but did not originate in Washington DC at all. It was selected as a bud sport on trees growing near Bahía Blanca in Southern Brazil. A few grafted trees were then sent to Washington DC in the USA on several occasions via the diplomatic system for distribution to other more favourable growing locations in Florida and California, hence the connection. The earliest introductions in the 1860's all perished, but an introduction to the USA in 1870, is the world wide source of all 'Washington Navel' oranges today. One wonders what became of the parent scion material of 'Washington Navel' in Brazil? The earliest navels known as "Brazilian Bahía Orange" in Australia, appeared at the Royal Sydney Botanical Gardens in 1828 from Brazil and introductions in 1870 of improved 'Bahía' came from the Portuguese Azores. The Riverland navels were imported by the Chaffey Brothers from the Californian 'Washington Navel' stock and planted at Renmark SA in 1890. is without doubt the most popular home grown orange in Australia, but did not originate in Washington DC at all. It was selected as a bud sport on trees growing near Bahía Blanca in Southern Brazil. A few grafted trees were then sent to Washington DC in the USA on several occasions via the diplomatic system for distribution to other more favourable growing locations in Florida and California, hence the connection. The earliest introductions in the 1860's all perished, but an introduction to the USA in 1870, is the world wide source of all 'Washington Navel' oranges today. One wonders what became of the parent scion material of 'Washington Navel' in Brazil? The earliest navels known as "Brazilian Bahía Orange" in Australia, appeared at the Royal Sydney Botanical Gardens in 1828 from Brazil and introductions in 1870 of improved 'Bahía' came from the Portuguese Azores. The Riverland navels were imported by the Chaffey Brothers from the Californian 'Washington Navel' stock and planted at Renmark SA in 1890.

The 'Washington Navel', is seedless of course and matures early in winter. You will need to remove the early crop in its first year or risk the weight of fruit, damaging the young tree. The fruit set is prolific and pretty regular each year. The fruits do however have a weakness in their navels, that does cause it to split with irregular watering or stress. While this doesn't cause the home gardener too much anguish, it is unacceptable commercially. It also has a juice that has a very short shelf life when squeezed. After six hours it starts to taste quite bitter, unless frozen.

The flowers on a 'Washington Navel' bloom and get pollinated in spring, but then take seven to ten months to mature and ripen. They can even stay on the tree for up to 13 months. Commercial growers use a "stop-drop" spray to keep them clinging for as long as four months, until they get the time to pick them or the price rises. They use a diluted 2-4,D spray with growth hormones such as gibberellic acid added, to keep the rind in a juvenile state. This practise is not recommended for home garden use, since the quantities of chemical used are infinitesimally small and the home gardener would not be able to buy or use these agents safely.

The 'Washington Navel' makes a small tree with a drooping habit and in Mediterranean climates, the fruit colour is a very rich orange colour, where as in the sub tropical areas, it is usually much paler. They need regular watering in hot areas during their fertilisation period, from September to October, or else the fruit will abort and drop. If the fruits do not develop at a steady rate they remain small and will split from the navel, so a regular feeding and watering program is recommended during their summer growth period. There are many new navel oranges currently under Plant Breeders' Rights (PBR) patent wraps, that may one day be available to home gardeners, but at best, they are only of interest to commercial growers. Some citrus propagators and speculators in Mildura Vic. and Renmark SA are pinning their hopes on an orange bonanza, by selecting and regsitering a very late season season navel that tastes really sweet, so their industry can tap the Japanese fresh fruit market, with a product that the USA and Brazil cannot match.

'Leng Navel' is an early season navel orange with thin skin and paler coloured smaller fruits, that is about two weeks earlier than the standard 'Washington Navel'. That might not sound much to get excited about, but it generally means a slight premium price per box to the grower. The juice spoiling agent, limonin, is also present in smaller qualities than in the 'Washington Navel', so it stores better when juiced. The 'Leng Navel' was selected from trees growing at Merbein NSW, but since the Leng family of Irymple Vic. distributed it, it then became know as the 'Lengs Navel'. is an early season navel orange with thin skin and paler coloured smaller fruits, that is about two weeks earlier than the standard 'Washington Navel'. That might not sound much to get excited about, but it generally means a slight premium price per box to the grower. The juice spoiling agent, limonin, is also present in smaller qualities than in the 'Washington Navel', so it stores better when juiced. The 'Leng Navel' was selected from trees growing at Merbein NSW, but since the Leng family of Irymple Vic. distributed it, it then became know as the 'Lengs Navel'.

'Lane's Late Navel' is often sold to home gardeners, although it is more widely grown as a commercial orange cultivar. It originated as a sport from the 'Leng Navel' on the property of a Mr L. Lane at Curlwaa NSW in 1954. It looks and tastes for all the world like a 'Washington Navel' but it fruits three months later and hangs on the tree up until November. The navels you see in the green grocers' shops after Christmas, will usually be imported Californian navels. is often sold to home gardeners, although it is more widely grown as a commercial orange cultivar. It originated as a sport from the 'Leng Navel' on the property of a Mr L. Lane at Curlwaa NSW in 1954. It looks and tastes for all the world like a 'Washington Navel' but it fruits three months later and hangs on the tree up until November. The navels you see in the green grocers' shops after Christmas, will usually be imported Californian navels.

'Red Navel' is a seedless sport taken from a 'Washington Navel' on Benham's orchard at Mundubbera Qld. Its fruit is set one week earlier than 'Washington Navel' and it's certainly got a better fruit colour, but I reckon it's no where as sweet. is a seedless sport taken from a 'Washington Navel' on Benham's orchard at Mundubbera Qld. Its fruit is set one week earlier than 'Washington Navel' and it's certainly got a better fruit colour, but I reckon it's no where as sweet.

'Valencia' is a seeded orange that ripens in summer and has fruits that are noticeably paler than the 'Washington Navel' when grown in a Mediterranean climate. In the tropics they do however colour up much better. While it is a very important commercial orange, in fact the world's leading commercial cultivar, it is not so popular with Australian home gardeners, unless you seek to supply an all-year-round supply of juice to the kitchen table. Then it will be vital to you. is a seeded orange that ripens in summer and has fruits that are noticeably paler than the 'Washington Navel' when grown in a Mediterranean climate. In the tropics they do however colour up much better. While it is a very important commercial orange, in fact the world's leading commercial cultivar, it is not so popular with Australian home gardeners, unless you seek to supply an all-year-round supply of juice to the kitchen table. Then it will be vital to you.

If you are visiting Spain in the region of Valencia, you won't find it planted there at all! Despite its Spanish name, it came into cultivation from selected trees growing in the Portuguese Azores and I think it most likely to have been taken there by the Portuguese from their Cochin exploits in south east Asia. While it arrived in Australia in the early 1800's it was not until the Chaffey Brothers planted it in the 1880's on their irrigation blocks at Renmark SA, that it gained notoriety. Today it's the bread and butter of 'blockies' in Victoria and 'blockers' in South Australia and probably in many of the other irrigated orange growing districts of Australia. It is the best juicing orange, characterised by a deep orange coloured juice and available throughout summer, makes it keenly sought after for concentrate, that is reconstituted for use later in commercial orange juice. Most of the imported orange juice concentrate that comes from Brazil is also from 'Valencia' crops.

In a hot dry climate where the trees are put under more stress, 'Valencia' sets fruit in biennial bumper crops, so that every other year is a lean harvest year. 'Valencia' flowers in late October and matures after 10 months, with harvest from August onwards, so that each tree will be carrying two crops at once. They keep on the tree when ripe for up to six months, but the juice quality is at its best after two months.

The 'Valencia' tree makes a large vigorous tree to 6 metres in height and although its fruit colour will not be as appealing as the 'Washington Navel' it should form part of a home garden orchard for fresh summer juice.

'Seedless Valencia' is a selection with far less seed, than the regular 'Valencia', but I wouldn't go so far as to say it's without seeds! The fruit matures slightly earlier than 'Valencia' and the leaves are quite large. It appeared as a bud sport on 'Valencia' growing at North Richmond NSW in the early 1920's. It also displays the 'Valencia' habit of fruiting in alternate years, when stressed. is a selection with far less seed, than the regular 'Valencia', but I wouldn't go so far as to say it's without seeds! The fruit matures slightly earlier than 'Valencia' and the leaves are quite large. It appeared as a bud sport on 'Valencia' growing at North Richmond NSW in the early 1920's. It also displays the 'Valencia' habit of fruiting in alternate years, when stressed.

'Joppa' is an orange cultivar with a rich juicy flavour and very few seeds in the fruit. It came from the Ottoman area of Palestine in 1877, which is now Tel Aviv-Yafo in the state of Israel. The 'Joppa' tree makes a stiff tree with thornless branches, where as most other oranges are armed with at least some thorns. It is a popular mid-season commercial variety, but of limited use in the home garden. is an orange cultivar with a rich juicy flavour and very few seeds in the fruit. It came from the Ottoman area of Palestine in 1877, which is now Tel Aviv-Yafo in the state of Israel. The 'Joppa' tree makes a stiff tree with thornless branches, where as most other oranges are armed with at least some thorns. It is a popular mid-season commercial variety, but of limited use in the home garden.

'Baker Sweet' is an early maturing orange with very few seeds in the fruit, which are also notably low in acid. That makes it popular with our Arab and Lebanese communities. is an early maturing orange with very few seeds in the fruit, which are also notably low in acid. That makes it popular with our Arab and Lebanese communities.

"Maltese Blood Orange" (syn. "Maltaise Sanguine" or "Tunisian Maltaise" in European markets) is a sweet juicy mid season orange that has the odd fruit with some blood-like colouring. It is rare to get the sort of blood colour that the Italian blood orange 'Moro' has. The "Maltese Blood Orange" is what the French regard as their tastiest sweet orange! I've waded through cases of them at the fruit markets to find a few good coloured ones in vain! You can't tell a good flesh colour from the skin either. They do apparently colour up better in hot arid climates with cold nights, whereas in maritime climes the coloration is poor, but it still has a great flavour. 'Moro' by the way, inspite of its great colour, is rather sour and not a popular eating orange. (syn. "Maltaise Sanguine" or "Tunisian Maltaise" in European markets) is a sweet juicy mid season orange that has the odd fruit with some blood-like colouring. It is rare to get the sort of blood colour that the Italian blood orange 'Moro' has. The "Maltese Blood Orange" is what the French regard as their tastiest sweet orange! I've waded through cases of them at the fruit markets to find a few good coloured ones in vain! You can't tell a good flesh colour from the skin either. They do apparently colour up better in hot arid climates with cold nights, whereas in maritime climes the coloration is poor, but it still has a great flavour. 'Moro' by the way, inspite of its great colour, is rather sour and not a popular eating orange.