GardenLine | House Plants | For Christmas and Chanukah: Oranges as Houseplants

Oranges first found their way into Europe from Asia during the Renaissance. They became the status symbols of the 'yuppies' of the day and were wintered in what were appropriately called "orangeries" - the prototype of the modern greenhouse. Each summer the container-grown trees were cumbersomely removed from the orangeries to summer in proud geometric array in the formal gardens of the estate.

Although few modern homeowners can afford the luxury of housing a full-grown orange tree, there are several dwarf varieties which are well adapted to life as a houseplant, given a sunny, south-facing window.

What to Expect

All have lovely white, star-shaped flowers with 5 petals and prominent stamens. Depending on the variety, the flowers are produced either singly or in clusters of up to 5. An added bonus is their fragrance and waxy texture.

The handsome foliage is dark green and leathery. Both thorny and thornless types are available. Most are under 1.8 m(6 ft) in height. All produce fruit but the fruit may take up to a year to develop.

Oranges abound with what are called "aromatic oils" which give them their typical citrus smell and taste. The presence of these oils is indicated by what appear to be transparent patches in the leaves and stems.

The Dwarf Varieties

The Calamondin orange (Citrus x citrofortunella mitis) is probably the most popular citrus in North American homes. A hybrid from the Philippines, it will begin flowering and fruiting when only 30 cm (1 ft) high. The fruit is 2.5-3 cm (1-1.5 in.) in diameter, bright orange, and very bitter to eat out-of-hand. However, it is ideal for marmalade or preserved in syrup. Once ripe, the fruit will remain on the plant for many months! It flowers profusely and will bear flowers and fruit at the same time. It is slow-growing, thorn-less, and makes a branching shrub 1-1.2 m (3-4 ft) when mature. It is probably the most satisfactory variety to grow indoors in that it fruits reliably and its size and shape are suitable for the average home.

The Meyer lemon (Citrus limon 'Meyer') is 1.2 m (4 ft) in height with 10 cm (4 in.) leaves. Its fruit is pale yellow, thin-skinned, and 7.6 cm (3 in.) in diameter. It, too, begins blooming when quite small. The flowers are pink in the bud stage, white when open, and exude a pleasant lemony scent.

The Otaheite orange (Citrus x limonia otaitensis or Citrus taitensis 'otaheite') is a Chinese hybird between a lemon and a Mandarin orange. The flowers are white with a purplish tinge. The fruit is yellow-orange, 5 cm (2 in.) in diameter, and produced in time for Christmas. The plant itself is small and thornless.

The Ponderosa lemon is orange-yellow with thicker-skinned, rougher fruit up to 11 cm (4 1/2 in.) in diameter.

Finally, the sweet orange (C. Sinensis) is the only dwarf variety with sweet-tasting fruit. It is 1.2 m (4 ft) in height with stronger stems, large leaves, and (alas) sharp spines! On the plus side, the fruit is solitary, 6-7.6 cm (2 1/2-3 in.) in diameter, and smooth-skinned.

Care of Citrus Plants

Citrus plants are not difficult to care for. They do well in standard potting mixtures with good drainage. They should be repotted when they become root-bound, about every 2 years. Place them in good light with a minimum of 4 hours of direct sun daily. A south- or west-facing window is ideal. Artificial lighting may also be utilized. Citrus like it relatively cool in winter (10-15C) and about 21C in summer. They may be placed outdoors during the summer months.

During the summer, citrus plants should be kept evenly moist. In winter they should be given less water but should never be allowed to dry out. Moisture should be even while fruit is developing and plants should be misted while in flower. Too much water during the winter months may cause leaf discoloration, leaf drop, or root rot.

Fertilize every 2 weeks during the summer months, when they are actively growing, with 20-20-20 mixed according to directions. Plants may be pruned in spring to keep them smaller or to improve their shape. Growing points may be pinched to encourage a more bushy growth. Excessively long branches may be pruned. Scale insects and spider mites may sometimes be a problem.

Propagation

Citrus plants may be propagated by seeds or cuttings. The seeds are called pips and should be planted about 2.5 cm (1 in.) deep. They should be kept evenly moist with a soil temperature of 21-23C. Seeds should germinate in 4-6 weeks and should be transplanted when 10 cm (4 in.) high. Seeds from store-bought oranges are fun to experiment with but will seldom grow true to variety. The majority will take 7-10 years to flower and fruit and even then may do it poorly or not at all. Eventually, they will outgrow your home. Seeds from limes, lemons and grapefruit are more likely to grow true to variety, but large mature size and late flowering and fruiting are still disadvantages.

Tip cuttings are an easy method of propagating the dwarf citrus varieties mentioned above. Ten cm (4 in.) cuttings of new growth should be dusted with a rooting compound and placed in a perlite-peatmoss mixture. This should be kept evenly moist (but not overly wet) in good, direct light. A plastic bag placed over the pot will hold in the humidity. Bottom heat of 21-23C is helpful. The cuttings should root in 6-8 weeks.

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Sustainable horticultural information, offered free of charge to the public with the support of the University of Saskatchewan Extension Division, the Department of Plant Sciences and the Provincial Government.