GROWING CITRUS

Selecting your tree

LEMONS (Citrus limon)

The Eureka lemon is a large, thick-skinned fruit that is produced year round. It is the bitterest of lemons available and so if you're often using lemons in cooking or for cleaning then this variety is a great choice. Eureka trees are mostly thornless and also come in a dwarf version.

The Meyer is a slightly sweeter variety that is actually believed to be a cross between a lemon and an orange. The fruit is medium-sized and thin-skinned; this variety is commonly sold in supermarkets and green grocers. Best cool-climate lemon. Dwarf Meyer lemons are also available but the full-size version can also be planted in a tub.

The Lemonade lemon is the sweetest of all the lemons and can be eaten straight off the tree. Fruits mid-winter.

Lisbon lemons are thin-skinned and highly acidic and are great for juicing. They are the most common commercial lemon variety grown in Australia. Fruits mid-winter to early spring.

ORANGES (Citrus x sinensis)

Washington Navel is a great eating orange that doesn't have seeds and is easy to peel. Lanes Late Navel is similar but the fruit ripens a few months later.

The Valencia has a long fruiting season and we usually sell the seedless variety. Great for eating and for juicing.

Blood Oranges have red flesh when grown in cooler areas but in coastal areas will have more orange-coloured flesh. Blood oranges have higher levels of antioxidants than other oranges (this is what causes the red pigment). They have a thick skin and a slightly different taste to other oranges. Popular in salads and as a garnish.

MANDARINS (Citrus reticulata)

The Emperor produces large fruit that is great for kids' lunchboxes as its loose puffy skin makes it the easiest mandarin to peel. Fruit ripens mid-winter.

Imperial mandarins are medium easy-peel fruits with a great flavour that ripen late autumn to early winter. This variety is the most commonly grown commercial variety in Australia.

The Hickson mandarin is medium-sized and ripens mid season. Tree is heavy-bearing.

Ellendale mandarins are large and ripen mid to late winter. They have a tighter skin and are very juicy with good flavour.

LIMES

Kaffir lime trees are grown for their leaves, which are commonly used in south-east Asian cuisines. The double leaves are a distinctive figure eight shape. The fruits are not edible.

Tahitian limes are the limes that are commonly sold in supermarkets and the fruits can be used in cooking, juicing or as a garnish in drinks. There is also a dwarf variety available.

Finger limes are Australian native trees that bear an unusual elongated fruit that has pulp which is caviar-like in appearance. This is great for sauces and jams as well as garnishes. They have very small leaves and lots of spikes but have the advantage of being better adapted to dryness, are resistant to fruit fly, and also require less fertiliser than traditional citrus.

CUMQUATS (Fortunella sp.)

Cumquats are an oval-shaped citrus fruit that can be used to make jams and conserves or eaten fresh. The cumquat tree is the best citrus for cold climates. There is also a variegated form available.

Planting and caring for your citrus tree

When choosing a spot to plant your tree, select a position that receives full sun for most, if not all, of the day. Citrus trees will also grow in partly shaded positions but they won't bear as much fruit and will be more susceptible to certain pests and diseases.

If you don't have a lot of room in your garden, citrus can be grown successfully in large pots on balconies or in courtyard areas, provided they will receive plenty of sun. There are dwarf varieties of some citrus that are ideal for growing in pots; these produce full-size fruit on a dwarf tree.

Citrus prefer a well-drained soil that is rich in organic matter. This can be achieved by digging some compost and well-rotted cow or sheep manure into the existing soil before planting. Cover with a layer of mulch but avoid placing it right up against the trunk of the tree as this will encourage disease.

Citrus are heavy feeders and require 2-3 applications per year of fertiliser; at the beginning of spring, summer and autumn is a good guideline to follow. There are many fertilisers that can be used: a synthetic citrus-specific fertiliser such as Osmocote or Garden Gold will provide all the necessary elements required for healthy growth and fruit, or alternately use a mix of blood and bone and potash to encourage fruiting.

Citrus are ideal for espaliering (growing flat against a building or fence). This is a great method for use in courtyard gardens as the tree takes up much less space.

Remove any plants, including grass, from beneath your citrus tree as the feeder roots are close to the surface and prefer not to have competition from other plants. Replace them with a layer of mulch such as sugar cane or rice straw.

Citrus need regular watering during dry periods to avoid premature fruit drop. They also prefer a warm climate but some varieties will tolerate cooler climates and light to moderate frosts. Not suitable for mountain climates.

 

Common Citrus Problems

Bronze Orange Bug (more commonly known as stink bug) is a sap-sucking pest that pierces the skin of newly forming citrus fruits and results in a sticky sap-like deposit inside the mature fruit. Netting the tree or spraying the bugs with a horticultural oil such as PestOil will help to control this insect while it is still young and green.

Citrus leaf-miner is probably the most commonly asked about citrus pest here at the nursery. This sap-sucking insect leaves a silvery trail on the upper surface of the leaf which often results in the leaf curling up. Most citrus in this region will have evidence of this bug to some degree and treatment is not necessary unless the infestation is severe as this bug won't affect the fruit. Treatment includes spraying the new growth with horticultural oil to prevent the insects laying their eggs on the leaves.

Fruit Fly larvae are common in citrus fruit in the Illawarra and unfortunately there is no longer a safe spray on the market for this pest. However there are certain controls available, including the use of nets and traps which attract male fruit fly and so help to break the breeding cycle as well as providing a way of monitoring population numbers. Come in and see us for more ideas.

Citrus Gall Wasp results in thickening and galling of the plant stems and can affect the vigour of the plant. This can be rectified by cutting off any affected stems and disposing of them in the rubbish bin (don't compost them).

Scale insects are small sap-sucking insects that secrete a sticky substance called honeydew on the leaves and stems of many plants, including citrus trees. Control these with white oil or pest oil and improve circulation around the plant.

Sooty Mould grows on deposits of honeydew that are secreted by sap-sucking insects. It is a black deposit that will hinder photosynthesis in the affected leaves. Controlling the sap-sucking insects will also control the sooty mould.

Nutrient deficiencies such as a lack of iron or magnesium can result in yellowing of the leaves which is a sure sign that a complete fertiliser is required. Use a slow-release or granular fertiliser that contains trace elements to rectify this problem.