Citrus plants reward your labours with spring flowers, winter fruits and year-round gloss, writes Jane Powers.
Of all the crops that make no sense to grow in this climate of ours, citrus plants are at the top end of the list. They have to be coddled, they drop their leaves if you upset them, and they fall prey to a host of eager sap-sucking pests.
If your pampered lemon or orange deigns to oblige you with fruit, the yield can be so miserable (often countable on the fingers of one hand) that it may seem a shame to eat them. Gold-plating them might seem more appropriate after all the time and energy that you have expended on them.
Yet citrus plants are a favourite of mine - just because they are so exotic and improbable. Imagine that! You can grow your own lemons, oranges, calamondins and kumquats in Ireland. The plants are alluring at any time of the year: when the white starry flowers pump out a powerful and sweet perfume (usually in spring); when the tiny, dark-green, pinhead-sized fruits appear and swell; and, finally, when they gradually colour up, which happens with the arrival of the cold weather. At this time of the year, when much else is quiet on the horticultural front, the yellow and orange fruits shine out from the glossy green leaves (which are also scented) like glowing lanterns, and light up the last days of winter.
Citrus fruits are everyday fare in the shops now, but they were weird and wonderful alien species when they were introduced to these islands, in the 16th century. Sir Francis Carew, who had the first orange trees in Britain, grew them outdoors, at Beddington in Surrey. His gardeners kept them warm in winter by surrounding them individually with wooden shuttering and heating the space with stoves. The diarist John Evelyn saw this arrangement in September 1658, and described the trees as being "planted in the ground and secured in winter with a wooden tabernacle and stoves".
By the following century citrus plants were grown in many big estates, and were overwintered in the "orangery", a specially-built house with a tiled floor and huge south-facing glass windows. It became quite the thing to hold parties in orangeries, where the scent of the blossom would have been intoxicatingly concentrated. There were several orangeries in Ireland, and a pretty one still exists at Fota, in
Co Cork. It was built in the mid-19th century, and restored in recent years.
Few of us have the space or funds for our own personal orangery (and the requisite gardeners to trundle the plants in and out, and to tend to their many whims), but there's no reason why we can't have a single citrus plant, or two, to give us a little taste of exotic climes.
Did I say taste? Well, as I mentioned earlier, don't expect great yields (for the first 10 or 20 years). But never mind: eating is a secondary or even tertiary pleasure, after the delights of sight and smell. Which is just as well, because the easiest-to-grow, and most fruitful, citrus plant is also the least palatable. But the calamondin is also one of the prettiest - with tiny, orange fruits, like doll's-house tangerines. As with many citrus fruits, its origins are not completely clear, but it is believed to be a cross between a kumquat and a mandarin, and it carries the unwieldy name of x Citrofortunella macrocarpa, although it is also sometimes known by its older binomial, Citrus mitis.
The calamondin tolerates a wider range of temperatures than most citrus, so it isn't bothered by a bit of cold, but, also (and more importantly), it can cope with our centrally-heated interiors in winter, and doesn't mind being indoors all year round. Most citrus plants (other than calamondin) need a dormancy period in the colder months, and should be kept in a well-lit room, such as a bright spare bedroom, a cool conservatory or, of course, your orangery. For lemons, oranges, clementines, mandarin, grapefruit and kumquat, a winter temperature of about five or six degrees, with a maximum of 12 degrees, is right.
Taper off the watering to just once or twice a month during this period, so that the root stock doesn't dry out. If all the leaves drop off (which they might, if there is not enough light), don't panic. They will grow back when the plant wakes up again in springtime. Meyer's lemon (Citrus x meyeri), which is a thin-skinned cross between a lemon and an orange, is hardier than most citrus plants, and can stand the very occasional spell of zero degrees.
But back to the easy-to-grow calamondin: it will happily snooze the winter away with your other citrus in a cold room. On the other hand, if you want to keep it awake and slowly growing, then leave it in the warmth, water it regularly, and feed it occasionally. The fruits are sour, very sour, and can be used instead of lemons or limes in drinks or on seafood. Or they can be pickled, preserved in syrup or made into marmalade. I suspect, however, that most gardeners follow the same course that I do, which is to leave most of the fruits decorating the plant (such a shame to pick them!) until they drop off, go mushy or shrivel.
All citrus like to be out in the fresh air and sunlight during the summer, in a sheltered and warm position (wind is one of the several things that makes them drop their leaves in a huff). If the weather is Mediterranean and hot, they should be introduced gradually to the sunshine, to avoid leaf scorch. They'll take plenty of water in the growing season (don't water during the hottest part of the day), and a sprinkling of pelleted poultry manure in spring. At Avoca Nurseries in Kilmacanogue, all the citrus plants are fed throughout the year with a balanced fertiliser, and the leaves are sprayed regularly with a seaweed-based foliar feed.
Citrus plants should be repotted every two or three years, in spring. They like a slightly acid compost: one part ericaceous compost, two parts John Innes number three and one part grit. Sapsuckers such as whitefly, scale insect and red spider mite adore them, so keep a close eye out for these enemy invaders. Misting them daily with water helps deter the last of these critters.
Those little lemons and oranges are some of the most labour-intensive crops you will ever produce. But they are also among the most treasured: each fruit is as precious as a jewel - which is why we who grow them are so reluctant to eat them. jpowers@irish-times.ie