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Introduction Citrus first came to prominence in the English-speaking world with
the discovery and use by Captain James Cook of the lime fruit as a ration for his men to
ward off the effects of scurvy en route to Terra Australis. The limes were
replenished at Rio de Janeiro, where the Portuguese merchants had been growing a range of
citrus for many years before Cook called. No doubt brought there and to the Mediterranean
areas of Europe, by the globe-trotting Portuguese, who had been busy trading and spreading
the Jesuits in the Far East and South East Asia. The citrus tribe had been in cultivation
in Cathay or China for several millennia. The fruit probably came to the west from the
Mandarin Empire, hence the common name.
One of the reasons the citrus tribe of oranges, lemons and
limes is so popular, is that they keep so well in storage. I recall seeing my grandfather
S.D. "Bill" Campbell in Mundoora SA, dry them in his chicken incubators and they
turned hard as rocks, but lasted years in storage. They also tasted the best I've ever
had, or maybe that was just my youthful taste buds. We now know its early discovery of
arresting disease was because of its high concentrations of vitamin C or ascorbic acid,
which has made it a popular choice as a fruit and fruit juice drink in winter. In fact due
to imported orange concentrate it's popular both here and everywhere else in the world,
all year round. There are so many growing areas in Australia and so many different orange
varieties that there is seldom a period in the whole calendar when fresh Australian
oranges are not available at your green grocer or super market. You can grow some sort of
citrus where ever you live in mainland Australia, from the tropics southwards.
The citrus family, known to botanists as the family
Rutaceae contains some of our most hardy cultivated plants. Globally there are over 1800
species in 150 genera found mostly in the tropics, sub tropical and temperate areas of the
southern hemisphere. Australia has about 320 species in 41 genera that belong to the
family Rutaceae. Few would recognise the popular Correa or "Native Fuchsia", the
"Brown Boronia" or the recently discovered and very rare native plant Neobyrnesia
suberea as relatives of the orange, but crush the leaves and you will instantly smell
the connection. Most members of the family Rutaceae have very distinctive oil glands in
their leaves, but it's the selected cultivars of some ten species that command most of our
attention.
The Chinese Imperial gardens have grown various citrus,
predominantly in containers, for at least a thousand years. In terms of the global
production, we are talking about some 2 million hectares producing over 63 million tonnes
of citrus fruits annually. There are about 45 million tonnes that are oranges, 8 million
tonnes of mandarins, 6 million tonnes of lemons and limes while 4.4 million tonnes of
grapefruits are picked. Australia's commercial production is over 600,000 tonnes per year
and that is about 83% oranges, mainly for juicing. There are no figures on domestic
production, but given that there are so many citrus trees in backyards, I'd guess that the
domestic consumption would be pretty high too. That's in marked contrast to Brazil and the
United States, which are by far the biggest commercial producers and yet their backyard or
home garden production is infinitesimally small.
There is huge potential for essential oil production too,
that is only just starting to be realised. Even with such aromatic oils in their leaves
and fruit skins, which cooks refer to as zest, they are still used rather sparingly in
cooking. Most folk would have recognised the "Kaffir Lime" leaf in the Thai Tom
Yom soup, or seen the sliver of lemon peal get dropped into the Spaghetti Bolognaise and I
remember when my Mum's one and only drink was a Hock lime and lemon at Christmas. The
juice of half a lemon was added to the infamous Hock, that became Riesling from the same
vines in the street where I grew up. As a kid every backyard in Brighton SA seemed to have
a lemon tree in it and in winter they were stripped bare as lemons were picked to ward off
winter colds. Today the same trees are laden with fruit but their elderly guardians don't
seem to pick them as much or else they are so bountiful, there is a great surplus. As a
young wool auctioneer I travelled all over rural South Australia for 'Uncle Elders' and I
reckon there would have had to have been at least three citrus trees in the farmyard of
every property I ever called upon. I recall admiring them on many occasions and frequently
being offered some oranges or mandarins as I left. These days I live in an inner suburb in
Adelaide and all my neighbours have a lemon and an orange tree in their tiny backyards and
they all share their bounty. Citrus thrive in my area because we don't have fruit fly to
ravage them or any other fruit for that matter, but they are the one type of fruit that
seems to thrive from the tropics to the desert, in clean air or in polluted suburbia.
They can however be quite demanding as young plants, but
when they mature many gardeners will brag that they never do a thing to their lemon tree
and it sets loads of fruit every year! I tear my hair out over that statement, but I hear
it every week and yet there is not a week that goes by, when someone doesn't ring me on my
weekly talkback gardening program (on Adelaide's ABC Radio 891, Sunday 10.05am-11am) with
a citrus query.
This is the tome to take the pressure off me giving the
same answers ad nauseam to my valued listeners and readers. It's not meant as a
guide to commercial growers who have very different requirements and a host of Plant
Breeders' Rights cultivars that are not available to back yard growers. They also have the
resources of their primary producing commodity groups and Primary Industries' research
officers to fall back on, for information. The home gardener is not so well served these
days with drastic cuts to all horticultural extension services in every state and
territory. If you have any further information, advice or criticism to pass on to me, I'd
love to see it in my mail box... Malcolm Campbell 81 Rose Terrace Wayville SA 5034. |
