by Deryn Thorpe

The trifecta of sweetly-scented white flowers, glowing edible fruits and glossy green leaves make citrus one of the best evergreen shrubs for Perth gardens.


Once upon a time the only two oranges available were the relatively seedless, late-fruiting Valencia orange and the sweet Washington navel orange which is still one of the very best eating oranges, ripening in June and July in Perth. Its fruiting is followed by the Navalina, which is similar to the navel, though the fruits are bigger. Now the range has widened and includes the fashionable Maltese Blood and Ruby Blood, both which have deep-red flesh and juice — though often they are more streaked than fully bloody in colour. The fruits keep on the tree for months once they ripen, improving in sweetness as they age.


Easy-to-peel mandarins are king of the school lunchbox because they are small and sweet. The most popular variety in Perth is the Imperial, which is the best early-fruiting variety, as it fruits before fruit flies are around in big numbers. Its fruiting is then followed by Cara, Ellendale and Murcott. When picking the fruits use sharp secateurs and cut back the stem by several centimetres to encourage new fruiting wood.


The smallest growing citrus is the cumquat. Varieties available in nurseries include Calamondin, Meiwa, the sweet oval fruited Nagami, which can be eaten skin and all, and ornamental variegated leafed varieties. They are excellent for pots, though most citrus can be grown this way if the pot is big enough.


There was a time when every backyard had a lemon tree — usually the thornless Eureka variety, which fruits and flowers all year round and grows to about 5m high and about 3m wide. Meyer is a smaller-growing lemon with a less acidic flavour as it is a cross between a lemon and an orange.


Piquent limes add a zing to food and drink. The West Indian limes are native to Malaysia and are more cold-sensitive than the Tahitian lime, growing best in tropical areas. Although named as a species, the Tahitian lime is thought to be a cross between the West Indian lime and a lemon or grapefruit. Fruit can be eaten when green but is still piquent when it ripens to yellow. It is the aromatic leaves and not the fruit of the Kaffir lime — a thorny native bush of Indonesia — which is used to flavour Asian food, especially curries. If you run out, the young leaves of any citrus make a satisfactory substitute.


Originating in Barbados, grapefruit are named because the fruit hangs in clusters. The most popular variety is Marsh, which is an almost seedless white-fleshed variety. Pink-fleshed grapefruit are now more fashionable and include Ray Ruby, Ruby Blush and Henderson. Don’t expect Perth-grown grapefruit to be as sweet as those grown in places like Carnarvon, where the higher evening temperatures result in sweeter fruit.


These are a red-orange colour and are crosses between a mandarin and grapefruit. The two most common varieties of the tart-yet-sweet flesh are Minneola (which has a bell shape with pronounced neck, few seeds and medium-to-big fruit) and the heavy-cropping and juicy Seminole.


There are six different varieties of Australian native citrus which come from rain forest areas. Plants are best in a position with afternoon shade. Best known are finger limes which are thorny plants bearing finger-shaped fruit with pearl-like pulp which makes a stylish garnish.

All parts of the citrus tree are useful.

The aromatic rind of the fruits is full of oil, which is used in the cosmetic, food, medicine and cleaning industries. Flowers of the bitter orange blossoms produce perfumed neroli oil; the leaves of some varieties are used in cooking, and the delicious flesh and juice of the fruit — which are said to stimulate digestion — are eaten fresh and turned into jams.


Citrus prefer full sun positions and are surface rooted, so avoiding underplanting and mulch out to the drip line. Fertilise lightly with an organic, pelletised complete fertiliser in late winter and spring, but water well before fertilising to avoid damaging the roots. Trees grown in Perth sands often have pale leaves. This is a symptom of nutrient deficiency and plants should be sprayed with complete trace elements. Keep trees to a managable size by pruning after harvest in winter to early spring, before bud break