General:
Citrus trees originate in Southeast Asia and India. The trees can live for 20-30 years and can start to bear fruit from 3 years of age. As a tree, they are ornamental in themselves as they are evergreen with bright glossy leaves. Citrus trees can be grown from Tasmania to Darwin. In cooler climates, citrus can be grown in pots and moved to warmer spots in winter or inside a greenhouse. For the growth of sweet fruit, at least 210 growing days are required.
Citrus include oranges, lemons, limes, grapefruit, tangelos, cumquat, mandarins. There are also native limes, which are edible, and the kaffir lime leaves are used extensively in Thai cooking.
Types:
Type
Variety
General information
Harvest times
Oranges
Washington
navel
Widely grown as it ripens in winter. Fruit is seedless and very sweet and easily peeled.
May to
September
Navelina
Small tree with sweet fruit.
end of April to May
Valencia
Medium to large fruit with seeds. Very juicy.
Generally biennial with large crop one season and not so large for the next season.
October to April
Blood
orange
Popular in Europe with reddish flesh. Very high in anti-oxidants. Good colouring of the fruit is obtained with very cold night temperatures.
Not popular in Australia
Seville
Comes from southern Spain and is grown as street trees. Very sour so mainly used for marmalade.
July to August
Lemons
Lisbon
Thorny tree with large crop of thin skinned fruit.
Winter
Meyer
Said to be a natural cross between a lemon and orange. Prolific fruiter and less sour.
Winter
Eureka
Best in warmer climates. Tangy fruit on thornless tree.
Spring to summer
Limes
Tahitian
Small bushy tree with pale yellow fruit that should be picked when green as it may rot when left on the tree.
Can be nearing all year round
Finger
lime (Australian native)
Usually a rainforest tree that can grow up to 10m. Fruit has taste similar to limes. The fruits can be green and cylindrical in shape, up to 100mm long and only about 20-30mm in diameter. They do have prominent thorns. Can be grown in a pot.
December
to March
Kaffir lime
This tree is only grown for its leaves and the rind.
Grapefruit
Marsh’s seedless
Most common variety with yellow skin.
June-
September
Ray ruby
Sweetest flesh that can be enjoyed without sugar.
Star ruby
The reddest flesh with high juice content and low acidity. Less vigorous of the grapefruit trees, needing good drainage and a lot of feeding.
Mandarins
Imperial
early
Vigorous upright tree. Tendency to over crop so thin to produce a good-sized fruit. Sweet fruit that peels easily.
June to
September
Emperor
Trees have tendency to last only 12-15 years. Thin and loose skinned fruit with pleasant flavour.
June to
July
Dancy
Deep orange/scarlet skin. Moderately juicy with slight acidic flavour.
June
Honey
murcot
Bright orange, sweet and juicy fruit with lots of seeds. Can be stored in the fridge. Fruit should be thinned.
August to
mid-October
Ellendale
Tight skin and hard to peel so not popular these days.
July to August
Hickson
Large fruit easy to peel with some seeds.
May to August
Tangelo
Minneola
Thin skin, a little difficult to peel. Very juicy and strong flavour.
July to August
Kumquat
Nagami
(oval fruit)
Skin does not peel easily but flesh is pale orange, juicy and only slightly acidic. Great for liqueur and marmalade.
July to September
Marumi
The
sweetest of the round kumquat. Can be eaten straight from the tree.
July to September
Planting
Planting is best done after there is no danger of frost (16ºC is best). Choose a sheltered position.
Citrus trees need:
* plenty of sun
* good drainage
* well prepared soil with rotted manure
* neutral pH
* 1 metre diameter of space around the planting hole as citrus have shallow root systems so other plants nearby will take away moisture and minerals from your tree.
* planting at the same depth as it was growing in the original container.
You can plant a ground cover under your tree once it is established or mulch well but keep the mulch away from the collar of the tree to avoid collar rot. Water well but do not over-water. In cooler areas, plant your tree near a north or west-facing wall. Train your tree to 3 or 4 main branches, cutting back vigorous shoots to a few buds in late winter.
Growing citrus in pots
Lemons, limes and kumquat grow well in pots. In Europe, orange trees were commonly grown in pots and brought out in summer and wheeled back into the greenhouse in winter. Pots can be made of wood, clay and plastic pots. Of course, the plastic pots are easier to move around. Choose a suitable potting medium as garden soil is too heavy for citrus and it does not drain properly. Water regularly as pots tend to dry out quickly, especially those made of clay and fertilise regularly (begin in early spring and end in late summer) as frequent watering will leach out minerals.
Harvesting
See the above table.
Pruning
Very little pruning is needed but you should always remove any shoots appearing below the graft.
Early imperial mandarin trees are quite bushy and are prone to overcropping. The denseness of the branches stops light reaching the middle of the tree. You can prune out the canopy of the tree to promote the growth of bigger fruit.
An ideal height for a citrus tree is between 3 and 4 metres so regular pruning may be needed to maintain a good height for harvesting.
If you do have to prune, then wait until after the danger of frost.
Note that dwarf varieties are now available if you have limited space and reach!
