Growing oranges and lemons in the UK is easy and takes very little effort. Limes can be grown too but require more tropical temperatures and do better in a greenhouse or conservatory when grown in the UK.
Lemon trees, Citrus x limon, and bitter or Seville oranges, Citrus x aurantium are the easiest citrus trees to grow. Both are vigorous plants and tend to tolerate the lowest temperatures. Most orange and lemon trees will require winter protection, though new hybrids are emerging that are pushing the boundaries of citrus hardiness.
How to grow orange and lemon trees
Grow orange and lemon trees in terracotta pots in a sheltered, sunny spot such as in front of a south- or west-facing wall. They do best in high humidity, if they are in a greenhouse or conservatory they will need misting daily. In summer, water around once a week, using rainwater if possible. Feed them weekly with liquid seaweed and a citrus fertiliser. Prune in spring, thinning out the centre of the plant so light and air can get in, and remove branches that look dried, thin, tired or lacking in vigour. Move indoors in winter, where it remains cool but frost-free.
How to plant orange and lemon trees
Plant lemon and orange trees in pots. It is best to opt for plain unglazed terracotta as they lose moisture quickly so it is hard for you to over water them. Citrus plants do not do well in waterlogged soil or in extreme cold temperatures. Planting in terracotta pots allow you to move the trees around from season to season. For the substrate try a 1:1:1 mix of loam, leafmould and horticultural grit, or John Innes No2 top-dressed with garden compost or well-rotted animal manure. Alternatively Henleaze Garden Shop stocks Citrus compost premixed for your convenience. Repot in spring every two to three years, moving to a slightly bigger pot each time. Leave a gap between the top of the pot and the top of the soil to let water pool when you water.
Caring for orange and lemon trees in summer
Once your citrus tree begins growing again in Spring, it is important to move the tree to a sunny position in the garden South facing is ideal. English weather is anything but consistent so it is important to protect them from sudden fluctuating temperatures. Look out for late frost forecasts and keep some horticultural fleece handy – you'll need it to cover and protect the new growth if frosts are predicted.
Prune the Citrus tree in the Spring once it is outside and producing new shoots. it is important to thin out the centre of the plant so light and air can penetrate. Remove branches that look dry and thin or generally lacking in vigour, also cut out any branches that appear at the base of the plant. To keep the plant a desired size trim them again in September, you dont have to worry about pruning too much, most citrus especially lemon trees are vigorous and will benefit from pruning and will produce more flowers and fruit on the stronger branches as a result.
On younger plants it is prudent to remove the majority of the fruit as it takes a lot of energy to produce. The aim is to encourage the tree to bear fewer but larger fruits until the tree is more mature. Pick any ripe fruits when you move the plants indoors in autumn, and again when you move them outside again, as ripe fruit can inhibit flower production.
Watering orange and lemon trees
Orange and lemon trees do best in high humidity. In summer, water around once a week, using rainwater if possible. If only tap water is available, let the water stand for 24 hours to let any chlorine evaporate. Water sparingly in winter – once a month is usually plenty – and a thorough soaking on occasion is much better than watering little and often.
Caring for orange and lemon trees in winter
In winter, orange and lemon trees will fare best in a cool, frost-proof area such as a garden shed or garage, cellar or unheated greenhouse. Centrally heated rooms indoors are to be avoided, which are too hot and dry. If you have little options other than a room indoors, then go for a Calamondin orange, x Citrofortunella microcarpa, which copes best with dry heat.
Growing oranges and lemons: problem-solving
Leaf drop: this is a sign of stress through too much heat, cold, incorrect watering or a lack of humidity, but not a disaster. See if reducing watering and increasing humidity helps.
Sticky leaves: these could be a sign of citrus mealybugs or scale insects, which thrive in warm, humid conditions. They excrete sticky honeydew that in turn, sooty moulds grow on. Wash the leaves every now and then with a soapy solution, and prune to improve ventilation. Under glass, bio-controls of wasps and ladybirds are effective.
Leaf damage: larvae of citrus leaf miners bore channels in leaves. Prune in autumn, removing all damaged material.
Yellow leaves: can be a sign of red spider mite, which is best controlled with bio-controls and high humidity. Citrus may also suffer from chlorosis as they don't tolerate lime. Draughts, low temperatures, over- or underwatering, or poor feeding can also lead to yellow leaves.