The calamondin orange tree, otherwise called citrus calamondin, Phillipine lime, calamansi lime or acid orange, is a small evergreen tree, with glossy mid-green leaves. White, fragrant star-shaped flowers are followed by very attractive small yellow/orange fruit, which are used like lemons or limes in drinks and food, or eaten raw for a pop of sweet-sour flavour, the taste somewhere between a lemon and a satsuma.
The scientific name of calamondin orange is x Citrofortunella macrocarpa, and it’s thought to be a natural hybrid between a mandarin and a kumquat.
How to grow calamondin orange
Grow calamondin orange in a terracotta pot in a sheltered spot in full sun, bringing it indoors in winter to a cool bright place until all risk of frost has passed. Prune in spring and feed weekly during the growing season, which continues through the winter.
Where to grow calamondin orange
Of all the citrus trees, calamondin orange is the most tolerant of lower temperatures, down to –5ºC. But, even in the mildest areas, it’s best to cultivate it in a pot so you can control the growing conditions, and give it shelter or move it indoors in winter. Outside, position the pot in a bright sheltered place in full sun or partial shade. Indoors, site it in a cool, frost-free place with lots of light.
How to plant calamondin orange
Like all citrus trees, calamondin orange needs a free draining, slightly acidic soil. Plant in a terracotta pot with drainage holes, as this is unlikely to become waterlogged. Make your own growing medium using equal portions of loam, leaf-mould and horticultural grit, or buy peat-free John Innes No. 2, ericaceous, or citrus compost.
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How to care for calamondin orange
Calamondin is relatively drought tolerant, and it's far better to under water than to water too much. Water all year round, allowing the top 10cm of the compost to dry out between waterings. Add a specialist citrus liquid feed to the water, full-strength in spring and summer and half-strength in autumn and winter. If you do not have a cool conservatory or frost-free green house, bring your calamondin orange indoors into the house - it’s the citrus that’s most tolerant of the dry air in our heated homes but will benefit from regular misting or being placed on a shallow tray with a layer of pebbles just covered in water that will evaporate into the foliage, raising the humidity. Every year remove the top 3-4cm of soil, taking care not to damage the roots, and replace with garden or citrus compost (general purpose composts are usually too alkaline). Repot in spring every three years, moving to a slightly bigger pot each time until you reach the maximum size that can be moved easily (at this point, annual top-dressing and regular feeding becomes more crucial).
How to harvest calamondin orange
Fruit swell from December and take a long time to ripen, becoming more orange and sweeter as spring progresses. You know when a calamondin is ripe when the orange fruit becomes soft, but if you plan to eat it, it’s better to harvest it earlier, as it has a better flavour when it’s still firm and turning from yellow to orange. To avoid damaging the thin skin of the fruit, use scissors or secateurs to cut it from the branch.
How to prune calamondin orange
A calamondin orange tree can live for more than 50 years and grow to seven metres tall in open ground. Prune your container grown tree to limit its spread (anything from 1m to 3m) so that it’s straightforward to move it into its winter quarters and easy to reach the fruit. Pruning also encourages the production of flowers and fruit on the remaining branches. Prune in spring, thinning out the centre of the plant so light and air can get in, and remove branches that look dried, thin, or lacking in vigour. Cut out any suckers that appear at the base of the plant. Trim again in September to keep plants to the desired size.
How to propagate calamondin orange
Calamondin orange can be propagated by softwood cuttings taken in the spring. Take 20cm cuttings of branches without flowers or fruit. Remove all but the top leaves and insert into a pot of free draining compost. Cover with a plastic bag or pot to create a mini-greenhouse and put on a bright windowsill. Within four weeks your cutting will start to produce new leaves, indicating that it has rooted. Remove the plastic bag and care for the plant as you would an established tree, potting it on as its rootball develops.
Calamondin orange is self-fertile and grows readily from seed. Leave a couple of fruit on the tree until the fruit is soft and the skin is a deep orange colour. Remove the seed from the flesh, use tissue paper to pat it dry, sow 2cm deep in a moist seed compost and keep at 60 degrees C. Germination occurs within three weeks.
Calamondin orange trees mature incredibly fast, and you will have fruit in two years! However, young plants use a lot of energy to produce fruit, so thin them out, encouraging fewer but larger fruits in the early years.
Pests and diseases
Overwatering causes leaves to turn yellow, cold draughts cause leaf drop, and underwatering causes leaves to curl up. Yellow leaves can also be a sign of red spider mites, which can be controlled by raising the humidity around the plant. Citrus mealybugs and scale insects will cause sticky leaves and can be controlled by occasionally washing the leaves with soapy water.
Advice on buying calamondin orange
- Calamondin orange is more tolerant of lower temperatures than other citrus trees but still thrives in a sheltered, sunny spot in neutral to acidic soils – make sure you have the right growing conditions before buying
- Inspect the plant and reject it if it has yellow or discoloured leaves, is dropping its leaves or there are signs of pests Remember, there are several quite different names for this lovely tree