At this time of year, one of the welcome splashes of bright colour in the garden comes from the plump fruit of oranges, lemons, mandarins, cumquats and grapefruit. The Hills District of Sydney, which broadly encompasses the area where I live, was once the citrus-growing capital of New South Wales. Many acres of land here were used for the growing of oranges and mandarins in particular, which had been brought to the colony by the very earliest settlers. The fertile shale-capped plateau of the area was found to be ideal for producing these fruits from the early nineteenth century onwards. My own grandparents owned a 30-acre citrus orchard in Arcadia in the 1920s, where they made a reasonable living from their produce. Later, citrus-growing moved to the Murrumbidgee Irrigation Area, where there were fewer problems with certain diseases, such as sooty mould, and a more reliable supply of water for the trees.
Much of what I have learned about growing citrus comes from a talk I heard a number of years ago from one of Sydney's experts, Mark Engall from Engall's Nursery at Dural. Lemon trees have been the traditional favourite citrus fruit in home gardens, and when I was a child, everyone seemed to grow one. They also seem to cause gardeners (myself included) a degree of angst in how to keep them healthy. In my current garden, I inherited a magnificent specimen of a 'Eureka' lemon, but I have had trouble keeping it as healthy as it should be, so I listened avidly to Mark's suggestions on how to look after them.
A key point seems to be to find the ideal spot in your garden for them - in a well-drained position in full sun. As with any planting, the soil should be prepared in advance, by digging over a reasonably sized area to at least a spade's depth, adding gypsum if there is a lot of clay and incorporating rotted organic matter. The roots of the plant should be teased out gently and the plant placed in a hole at least twice the width of the root ball. The plant should be put in at the same depth it was in the container, with top of the root-ball should be level with the surrounding soil. Water well and keep it well watered for the next few weeks. Once established, citrus trees need regular watering and love to be fed every few months, using something like Organic Life or Dynamic Lifter. They also need to be free of competition from grass growing around their surface roots, so a good area should be left clear under the tree, which can then be kept covered with an organic mulch to conserve water and protect the roots from heat. The mulch can be scraped aside whenever you are going to apply fertiliser. Don't ever allow the mulch near the trunk, as this can cause fungal problems.
One important point Mark made was that young plants should not be allowed to fruit for the first two years, as apparently this will severely affect their growth during that time. To produce larger fruit on established trees, it is a good idea to remove some of the young fruit when it is very small, or even take off some of the flowers. Although pruning is not essential (except to remove dead wood), they don't object to pruning and this is one way to reduce the number of fruit on the tree. Pruning can also be used to produce formal effects such as standards or espaliers out of your citrus trees. It is also a way to rejuvenate old trees: my own lemon tree had become very tall, straggly and unthrifty over the years so I gave it a severe prune about five years ago and it has recovered very well and producing fruit well again.
I also have a Tahitian lime tree (Citrus aurantiifolia) and a lemonade tree (Citrus limon x reticulata), which are both bearing abundant fruit at the moment. The lemonade tree is said to have been derived from a cross between a lemon and a mandarin. The delicious fruit can be eaten straight from the tree, and has the sweetness of a mandarin with a lemon tang. Lime and lemonade trees enjoy the same conditions as other citrus trees. A dwarf-growing version of the lemonade tree is available these days.
Citrus trees, especially the smaller types, can be grown successfully in pots, repotting as they grow until they finally are placed in a decent-sized container. As with citrus planted in the ground, they need regular fertilising and watering. There are various pests which attack citrus - not all affect the fruit, but they can distort the foliage. Eco Oil can be used to control most of the pests, which include leaf miner (prevalent in summer and autumn), the horrid bronze orange bug (which can affect the fruit as well as the foliage), scale and aphids.
I love to see citrus trees growing with similarly coloured plants in the vicinity, and there are some lovely examples out at the moment: the petite tangerine daisies of shrubby Tagetes lemmonii, the mountain marigold; the bright yellow, simple blooms of Euryops species; the slim yellow and orange trumpets of Justicia floribunda (syn. J. rizzinii); or the golden coins of Reinwardtia indica, sometimes known as linum. All these plants grow easily in our Sydney climate and will cheer up the gloomy days of winter ahead!
This blog was originally posted on 6 June 2010; updated 28 June 2020.
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