Citrus × microcarpa – Calamondin

Parentage and cultivated origin of Citrus × microcarpa – Calamondin

Citrus × microcarpa is a cultivated hybrid of Citrus japonica × Citrus reticulata.

Calamondin is especially associated with the Philippines, where it is widely grown as both an edible and ornamental citrus. It has also been cultivated in southern China and other parts of East and Southeast Asia.

Growing Calamondin indoors

• Container and mix: Calamondin has a compact root system, so use an airy citrus mix in a pot that closely matches the roots. When the roots have filled it, move up by one pot size; this helps the mix dry evenly.
• Light: Give direct sun to keep the crown dense and support repeated flowering. A bright east-facing window may need supplementary light, and stronger outdoor sun should be introduced gradually.
• Watering: A heavy crop can raise water use quickly. Once the surface has dried, lift the pot; water when it feels lighter and the centre is lightly moist, then let excess water drain. After leaf or fruit drop, reassess how quickly the pot is drying.
• Temperature and humidity: Keep the plant frost-free. When growth and water use slow, a bright, slightly cooler position is suitable. Its dense crown does best with moderate humidity and some air movement, away from hot, dry radiator air.
• Feeding and crop: Feed while the plant is actively growing or developing fruit, following the label. Keep the naturally close-branched shape and support or thin fruit when a young twig begins to bend under the weight.

Calamondin problems in a compact crown

• Green leaves and fruit drop after a move: A sudden shift in light, temperature or how quickly the pot dries can trigger shedding. Keep Calamondin in one bright stable position and base watering on moisture below the surface and the pot’s actual drying speed.
• Leaves wilt while the small pot stays wet: Dense, continuously wet potting mix can damage the fine roots quickly. Look for roots that have turned soft and brown and note any sour smell from the mix. If decay is present, use clean, disinfected tools to cut away soft or rotten tissue back to firm, healthy tissue and discard the removed material, then repot. Otherwise, leave the root system intact. The root-rot guide covers the recovery steps.
• Sticky leaves, bumps or black sooty growth develop inside the crown: Scale insects can remain hidden on fine twigs and leaf undersides. Isolate the plant, inspect the dense centre and remove insects you can reach. Where treatment is necessary, use only a product labelled for the pest and plant, with repeat applications made strictly as directed on the label. See the scale guide for identification.
• Tender new leaves become twisted with pale tunnels: Citrus leafminer feeds inside young leaves. Keep mature green foliage, remove only badly damaged tender growth when necessary and monitor the next round of new leaves; established plants often continue growing despite limited damage.

If the cause is still unclear, send us clear photos of the whole plant, the affected area and the potting mix so we can help you narrow it down.

Keep Citrus × microcarpa – Calamondin away from pets

• The fruit flesh is edible, while leaves, peel and other plant material can irritate cats and dogs.
• These parts contain essential oils and psoralens that may cause vomiting, stomach pain, unusual tiredness or skin irritation.
• Contact a veterinarian if a pet chews the plant or develops symptoms. Seek medical advice if a person becomes unwell after exposure.

Why is it called Citrus × microcarpa?

Citrus is the classical Latin name used for citron and related citrus plants. Microcarpa means ‘small-fruited’.

Carl Linnaeus established the genus Citrus in 1753 in Species Plantarum, page 782.

Alexander von Bunge first described Citrus × microcarpa in 1833 in Enumeratio Plantarum in China Boreali, page 10.