How to Grow Juicy and Vibrant Citrus Fruit Plants For Added Fragrance and Colour to Your Garden
Fight your way through the forests of stacked and wrapped Christmas trees in the garden centre and you will probably find an assortment of small citrus bushes in pots for sale. With their glossy dark leaves and hanging fruit like Christmas baubles, they look like ideal gift ideas. Indeed, citrus trees are incredibly rewarding to grow: apart from the edible fruit, many have edible leaves and flowers and are beautifully scented.
They are perhaps not for the low-maintenance gardener, although - like many plants - once given the right conditions they can thrive for years. The right conditions, however, can be quite specific.
How to Grow Your Own Citrus Plant
First off, citrus plants are not hardy. If you are thinking of buying one as a gift at this time of year, make sure the recipient will be able to keep it indoors over winter in a cool, light space. In the south of the UK, you may get away with keeping plants on a sunny sheltered patio close to the house, but they really don't like temperatures below 7-10 degrees and you must be ready to bring them indoors if frost threatens.
Secondly, they may not like frost, but they do like variation in temperature: warm during the day, cool at night. When you bring them indoors, they will do best in an unheated room that gets down to around 12 degrees at night - try not to place them near a radiator.
Don't be too quick to repot them: the plants will happily stay in the same pots for 2-3 years. Do buy two small pots of citrus feed: one for summer and one for winter. They will last forever and your plants will appreciate it. The soil should be kept moist (not wet) in the summer and can dry out a bit more in winter.
A happy citrus plant will grow throughout the year, albeit much more slowly in winter. The fruits are slow to grow and mature, which means that you will often have new leaves, flowers and fruit forming all at the same time. Some dropping of immature fruit is quite normal. While some leaf fall in winter is acceptable, dropping leaves is usually a sign that the plant is not happy.
If the leaves that have been shed are dry and crinkly, the soil is probably too dry; if they're floppy, let the soil dry out some more. The plant will usually recover. Check plants indoors for the dreaded red spider mite as well. They will leave fine cobwebby filaments between the leaves: wipe these away and then wipe the underside of leaves as well - this is where the mites and their eggs will settle.
Oranges are Not the Only Citrus
Citrus plants hybridise freely and there are a bewildering number of varieties available. All derive, botanists think, from three varieties found in Asia: the Citrus maxima, or the pomelo, which looks like a giant grapefruit with thick peel; Citrus medica, the citron (a direct ancestor of lemons and limes) and Citrus reticulata or the mandarin. The common orange is a cross between the pomelo and mandarin; lemons are the love child of bitter oranges (themselves another offspring of pomelo and mandarin) and citrons.
The most common varieties found in garden centres are probably lemons, especially 'Eureka', which is a reliable cropper and will keep your gin and tonic topped up all year round, and calamondins, a citrus cross with tiny orange fruits. I'm told they make great marmalade, should you ever have anything approaching a glut.
Kaffir limes also produce wonderfully fragrant fruit, the zest of which is much used in Far Eastern cooking. Of all the citrus plants I've grown, kaffir limes thrive best on benign neglect. Meyer lemons, a lemon/mandarin cross, produce small but very flavourful fruit, though I have found them difficult to overwinter. Yuzu, another bitter orange/lemon hybrid, are relatively new to our shores, but much used in Japanese cooking. Both Meyer lemons and yuzu are available from Plants4Presents. If you buy a yuzu plant, beware of the seriously wicked thorns.
The adventurous citrus buyer can look out for bergamot plants (Citrus x bergamia) grown for their perfume and Buddha's hand (Citrus medica var. sarcodactylus, available from Suttons), which has its segments growing on the outside rather than the inside of the fruit and looks like a halfway house between a bunch of bananas and Bart Simpson's head.
Christina Erskine is a garden designer based in north London. She also grows her own fruit, vegetables and edible flowers in a tiny back garden and on two allotments. Find her at urbanhedgerow.co.uk and on Instagram @christina_erskine.