Species family Rutaceae
Attractive shiny green foliage and attractive fruit colour home-grown fresh citrus fruits are nutritious to eat. The peel is appreciated when added to sweet or savoury dishes and juice the fruit for healthy and refreshing drinks. The smell of citrus blossom is prized in perfumes and many other species of plants are sought out that mimic their scent.
The cold-hardiness of fruiting citrus types varies significantly. This often influences where certain varieties or types can be grown successfully, as regular frost damage must be avoided. In summary:
Very sensitive: citron, lime and lemon are susceptible to injury even by very light frosts.
Moderately susceptible: grapefruit, pummelo and sweet oranges.
Cold-hardy: seville, mandarin and the Meyer lemon.
Very cold-hardy: cumquat.
Citrus trees grow best in deep well-drained, sandy loam soils preferring a soil in the range of PH 6–7. The maximum amount of sunlight is desirable for the growth, setting and maturity of fruit. Bare rooted trees are planted in late winter or early spring (August-October). Mulching (keeping the trunk clear) will help reduce weed competition also soil temperature fluctuations, which can assist early establishment. Mulching will also dramatically reduce surface evaporation from around the young trees, allowing longer intervals between irrigations. Avoid positions that are low light, frost-prone, or exposed to strong winds.
Protect the young tree roots during planting with mud slurry. After the initial watering at planting, the soil surrounding the young trees should remain humid and not be allowed to dry out. Citrus are relatively shallow-rooted and need regular watering with even moisture throughout their root zone. This is required from flower, bud formation, through to fruit set to retain a good crop. Provided adequate irrigation is available, trees are tolerant of hot conditions, although if exposed to high temperatures fruits may become sunburnt. Owing to their shallow roots avoid digging nearby and regularly add composted, organic matter to the soil. Pruning should be performed before or during flowering with an emphasis placed on removing weak or dead branches, crossover limbs, water shoots, or undesirable limbs.
Thinning the fruit in January to February will increase fruit size and assist stored nutrient reserves for the winter. Fruit matures from May onwards and will improve in mild >30 degree Fahrenheit conditions. Fruit exposed to sun on the outside of the tree will mature first with fruit inside the canopy maturing several weeks later. Early harvesting of ripening fruit takes the load off the tree and allows the smaller remaining fruit to increase in size. Taste test because colour is not a reliable indicator of maturity, many oranges turn from green to orange before they are fully mature. Do not leave until they start dropping because it may affect next seasons bounty.
Most fresh citrus will keep at room temperature for a couple of weeks. For best results, store citrus in a plastic bag or the crisper drawer of your refrigerator. Peel from citrus can be zested and stored in a glass (plastic is affected by the oils) jar in the freezer. Dried limes are popular in Persian cooking. Jams, marmalades and sauces can use up surplus fruit and sorbet can be frozen in the hollowed out skins.
Varieties Suitable for the Sydney Basin
Many varieties are suitable for our Sydney Basin and the mild coastal areas north of Sydney producing favourable growth and early maturity because of our high summer and winter temperatures.
The fruit is used for culinary and non-culinary purposes throughout the world – primarily for its juice, though the pulp and rind are also used, mainly in cooking and baking.
Lemonade Tree – medium sized tree producing heavy crops of medium sized mild flavoured fruit throughout the year. Not as sour as standard lemons and makes a lovely refreshing lemonade drink.
Meyer Lemon – rounded fruit with thin, smooth skin, sweeter, juicier fruit than other lemons, grows in humid, tropical climates too.
These are generally small and an excellent source of Vitamin C they can be a great substitute for lemons.
Tahitian Lime (Citrus x latifolia) does well in the garden or in pots, this lime turns yellow when fully ripe, but can be used in its green stage also. Very good lime flavour, useful in Thai cooking, refreshing drinks, fish dishes etc.
Kaffir Lime (Citrus hystrix) grown for their culinary leaves and because the leaves are constantly being picked for cooking, the plants usually remain small in size. They also make good pot specimens.
Native Finger Lime (Citrus Australasica) fruit range in size from 6 to 12 cm in length and come in a wide range of colours including green, yellow, purple and pink to bright red. The pulp of the fruit is unique with a ‘caviar like’ appearance that also comes in a wide range of colours as a result of flowering times and climatic conditions.
(Citrus Reticulata) is a variety of the orange family.
Imperial Mandarin are the first to be harvested each season. This yellow-orange mandarin is available through autumn and winter and is easier to peel and contain less seeds than most varieties. Imperials originated in Australia, being first recognised in Sydney in 1890.
Hickson Mandarin originated in Queensland and is a mid-season variety available throughout winter. They are recognised by their brilliant, bright orange skin that becomes slightly puffy later in the season making them easier to peel.
Honey Murcott Mandarin is a delicious, late maturing mandarin, coming in between August and October in warm areas, later in cool spots. Large sized fruit with thin skin, excellent sweet flavour and high juice content.
These are a versatile citrus tree contributing ornamental value with their ever abundant supply of flowers and sweet fruits. Featuring glossy green foliage and highly scented flowers followed by beautiful coloured fruits they are perfect for the home orchard, containers and tubs.
Navelina (Spanish variety) produces fruit of excellent quality and brilliant colour, very early in the season. Good fruit size and naturally develops an outstanding deep red orange skin which is very attractive. Trees are compact and smaller growing than most varieties of orange.
Valencia Orange is very Juicy, almost seedless and crops over a long period of time. It has high heat requirements and takes 12 months or more to ripen but can be left on the tree until required.