How to grow Cumquat in Australia
Cumquats are small, compact citrus trees with fragrant white flowers in spring and little orange fruit that is eaten skin and all. They are more cold tolerant than most citrus and grow and fruit well in pots, which makes them one of the easiest citrus for courtyards and cooler gardens.
📖 Our full guide: How to Grow Cumquat in Australia
At a glance
When to plant by region
| Region | When to plant | Regional note |
|---|---|---|
| South East Queensland | March to September | |
| Northern Rivers NSW | March to September | |
| Sydney & Coastal NSW | March to September | |
| Melbourne & Victoria | September to November | The hardiest citrus for Melbourne. Plant Sep to Nov in a sunny bed or a large pot. |
| Adelaide & SA | March and April, September and October | Plant Mar to Apr or Sep to Oct. Thrives in a bed or a pot; keep pots watered through heatwaves. |
| Perth & WA | March to September | |
| Tasmania | September to November | Plant Sep to Nov in a warm sheltered bed or a pot. After Meyer lemon, the most reliable citrus in Tasmania. |
| Canberra & ACT | November | The hardiest citrus for Canberra. Plant in November after the last frost in a sunny sheltered spot or a pot, and cover young trees on frosty nights. |
| North Queensland | May to September | Plant May to Sep in the dry and water regularly until the wet arrives. Grows well in a large pot. |
| Darwin & Top End | May to August | Plant May to Aug in the dry and water regularly through to the wet. Grows well in a large pot. |
Not to be confused with: Calamondin, which is a cumquat and mandarin hybrid often sold as a cumquat, and Mandarin, a larger, easy-peeling citrus.
Where to plant
Give a cumquat full sun, at least six hours a day, and free-draining soil. Like all citrus, the roots die in waterlogged ground, so on heavy clay or in a low spot plant on a raised mound rather than digging a deep hole into the clay. Cumquats grow in most parts of Australia except mountain areas, and they are more cold tolerant than other citrus, but young trees still need protection from frost.
Keep grass and weeds out of the root zone and mulch with compost or another organic mulch, keeping it clear of the trunk.
- South East Queensland, the Northern Rivers, Sydney and Perth: plant from March to September.
- Adelaide: plant in March or April, or September or October. Keep potted trees well watered through heatwaves.
- Melbourne and Hobart: plant from September to November in a sunny, sheltered bed or a large pot. In Tasmania it is one of the most reliable citrus, along with Meyer lemon.
- Canberra: plant in November after the last frost, in a sunny, sheltered spot or a pot, and cover young trees on frosty nights.
- North Queensland and Darwin: plant in the dry season (May to September in North Queensland, May to August around Darwin) and water regularly until the wet arrives. In the Darwin region cumquats fruit all year round.
Choosing a variety
| Type | Notes |
|---|---|
| Nagami | Oval fruit with a sweet skin and tart flesh. Thornless, vigorous and productive, and the type most often grown |
| Marumi | Round fruit on a tree with short, slender thorns |
| Meiwa | Round fruit, considered sweeter than Nagami but a less vigorous tree |
| Calamondin | A cumquat and mandarin hybrid, often sold as a cumquat. Sour, juicy fruit for marmalade, marinades and dressings; upright and ornamental |
Buy a grafted tree. Seedling cumquats are often very thorny and give poorer fruit. Trees grafted on dwarfing rootstock stay small enough for a pot. Names are used loosely in nurseries, and calamondin is sometimes labelled Marumi or Australian cumquat, so check the label for the fruit shape and use you want.
How to plant
- Prepare an area about 1.5 m wide by digging in compost or well-rotted manure. Add gypsum to clay soil, or build a mound if drainage is poor.
- Water the tree in its pot well before planting.
- Dig a hole wider than the pot but no deeper, and plant at the same depth the tree sat in its pot, with the graft union above the soil.
- Water in deeply, then mulch, keeping the mulch clear of the trunk.
- Keep the soil moist, but never soggy, through the first summer while the tree establishes.
Watering and feeding
Water deeply once or twice a week, depending on the weather, rather than giving light sprinkles. Cumquats need the most water while the fruit is forming in spring and early summer. Potted trees dry out much faster than trees in the ground, so check them often in hot weather.
Trees in the ground can be fed with a citrus fertiliser in late winter (August) and late summer (February), alternated with a pelletised organic fertiliser such as composted chicken manure. Feed potted trees more often, about every six to eight weeks through the warm months, or use a slow-release fertiliser in spring and early summer. Water well before and after feeding.
Pruning and care through the year
- Prune lightly to shape the tree and remove dead twigs, which carry the fungus that causes melanose.
- In the first year or two, pick off most of the young fruit so the tree puts its energy into growing a strong frame.
- Cumquats take well to clipping and are often grown as hedges, standards or topiary.
- Yellow leaves with dark green veins usually point to iron deficiency, often in alkaline soil. A chelated iron product and sulphur to lower the pH can help.
- Citrus gall wasp: cut out swollen galls on stems between April and June, or slice the top off each gall in mid to late winter, before the wasps emerge in spring.
Harvesting
Cumquats ripen from autumn into winter in southern gardens, depending on the variety. Because the sweet skin is the point of the fruit, wait until it is fully orange with no green patches. Citrus does not ripen further after picking, but ripe fruit holds well on the tree, so pick as you need it.
Picked fruit keeps for a couple of weeks in the crisper drawer of the fridge.
Growing in pots
Cumquats are among the best citrus for pots. Use a pot at least 40 cm wide with several drainage holes, and a quality, free-draining potting mix suitable for citrus. Do not jump straight to a huge pot; move the tree up a size as the roots fill the old one. Water more often than a tree in the ground, feed every six to eight weeks through the warm months, and turn the pot every few months so the tree grows evenly.
Using it
Eat Nagami and Meiwa cumquats whole, skin and all: the rind is sweet and the centre is tart. Sour types such as calamondin are best cooked. All cumquats make good marmalade, and the fruit can be candied, preserved in syrup or brandy, or sliced into salads and baking.
Companion planting
Like all citrus, cumquats do best with their root zone clear of competition, so keep lawn and weeds back to the edge of the canopy. Low plants that feed the soil are fine near the edge.
Good companions
- Comfrey Its leaves can be cut and laid under the tree as a mulch that feeds the soil. Keep it away from the trunk, and note it is hard to remove once planted.
Pests and diseases
Cumquats get the same pests as other citrus, though usually less badly. Most problems are insects on new growth.
Pests to watch for
- Citrus gall wasp Lumpy, woody swellings on young stems, visible from autumn. Prune or peel them before the wasps emerge in spring.
- Bronze orange bug Shield-shaped bugs, green to orange when young and bronze-black as adults, on new shoots. They squirt a liquid that burns, so wear gloves and eye protection.
- Leaf miner Silvery, winding trails in new leaves, which curl and distort. Mostly cosmetic on established trees.
- Scale Small bumps on leaves and stems, sticky honeydew, black sooty mould and ants.
- Caterpillars Chewed new leaves. Several native butterfly caterpillars feed on citrus; a few on a healthy tree do little harm.
Diseases to watch for
- Melanose Small, raised, dark brown spots on young leaves, twigs and fruit, spread from dead twigs in warm, wet weather.
Common questions
Can you eat cumquats raw?
Yes. Nagami and Meiwa cumquats are eaten whole, skin and all. The skin is the sweet part and the flesh is tart, so the two together give the flavour. Sour types such as calamondin are better cooked into marmalade.
When are cumquats ripe?
When the skin is fully orange with no green left on it. Most southern trees ripen from autumn into winter; in the Darwin region they fruit all year. Citrus does not ripen after picking, so leave the fruit on the tree until it is fully coloured.
Can I grow a cumquat in a pot?
Yes, they are one of the best citrus for pots. Use a pot at least 40 cm wide with good drainage holes and a quality citrus potting mix, water more often than a tree in the ground, and feed every six to eight weeks through the warm months.
What is the difference between a cumquat and a calamondin?
A calamondin is a hybrid of a cumquat and a mandarin. It is often sold as a cumquat, and its fruit is round, sour and juicy, so it is mostly used for marmalade, marinades and dressings rather than eaten fresh.
How big does a cumquat tree grow?
Most cumquats grow to about 2 to 3 m in the ground, and stay much smaller in a pot or on dwarfing rootstock.
Will a cumquat grow in a cold climate?
Cumquats are more cold tolerant than most citrus and grow well in Melbourne and even Tasmania. In frosty areas such as Canberra, plant in late spring after frost, choose a sunny, sheltered spot or a pot, and cover young trees on frosty nights.
Why are my cumquat leaves turning yellow?
Yellow leaves with green veins usually mean iron deficiency, often because the soil is too alkaline. Evenly pale older leaves suggest the tree needs feeding. Waterlogged soil also causes yellowing, so check drainage first, especially in pots.
Sources we checked: Burke's Backyard: Cumquats; City of Darwin: Kumquat (community orchard fact sheet); Gardening Australia: Harvesting Citrus; Organic Gardener: Easygoing cumquats; Yates: How to grow cumquat; NSW DPI: Melanose (domestic citrus fact sheet); Agriculture Victoria: Citrus gall wasp; Gardening Australia: Citrus Care; University of Florida IFAS: Kumquat.