How to grow Cumquat in New Zealand
Cumquats, also spelt kumquats, are small, ornamental citrus trees covered in little orange fruit through winter. They are the hardiest citrus for New Zealand, handling light frost better than other citrus, and among the easiest to grow in a pot on a sunny deck. The tart fruit is eaten whole, skin and all, or made into marmalade and preserves.
📖 Our full guide: How to Grow Cumquats in New Zealand
At a glance
When to plant by region
| Region | When to plant | Regional note |
|---|---|---|
| Northland | September to November | |
| Auckland | September to November | |
| Waikato & Bay of Plenty | October and November | Plant after the last frost. Handles inland Waikato frosts better than other citrus. |
| Central North Island | November | The hardiest citrus for the plateau. Plant in November in a sheltered spot or a pot. |
| Wellington & Lower North Island | October and November | Plant in spring. The easiest citrus here; a pot on a sheltered sunny deck works well. |
| Nelson & Marlborough | October and November | Plant after the last frost. Very reliable in Nelson's sunshine. |
| Canterbury | November | The hardiest citrus for Canterbury. Plant in November in a sheltered spot or a pot you can move. |
| Otago & Southland | November | Marginal. Best in a pot on a sunny, sheltered deck, moved under cover for winter. |
| Central Otago | Not suited | Hard winter frosts will kill it outdoors. Keep a potted tree under cover over winter. |
Where to plant
Plant cumquats in full sun in slightly acidic, well-drained soil, in a spot sheltered from cold wind. They tolerate light frost better than other citrus, but young trees still need protection on frosty nights. In cold districts, grow one in a pot that can be moved somewhere sheltered or under cover in winter. Citrus are self-fertile, so one tree crops on its own.
- Northland and Auckland: plant from September to November in a sunny spot.
- Waikato and Bay of Plenty: plant in October or November after the last frost. Cumquats handle inland Waikato frosts better than other citrus.
- Wellington and Nelson and Marlborough: plant in October or November. A pot on a sheltered, sunny deck works well, and cumquats are very reliable in Nelson's sunshine.
- Central North Island and Canterbury: the hardiest citrus for these regions. Plant in November in a sheltered spot or in a pot you can move.
- Otago and Southland: marginal. Best in a pot on a sunny, sheltered deck, moved under cover for winter.
- Central Otago: hard winter frosts kill cumquats outdoors. Keep a potted tree under cover over winter.
Choosing a variety
- Nagami: oval fruit, the usual choice in New Zealand.
- Meiwa: round, spicy-sweet fruit, excellent for marmalade, preserves and candying. A showy, smaller shrub, ideal in a container, and described by Waimea Nurseries as the hardiest of all citrus.
- Marumi and variegated forms: round fruit, and a decorative form with variegated leaves and fruit.
How to plant
- Dig a hole twice as wide as the root ball and to the same depth.
- Tease out the roots and cut away any that circle the pot.
- Plant at the same depth as before, with the graft union above the soil, and backfill, firming gently.
- Form a ring of soil around the root zone to hold water, water in well and keep the soil moist for several weeks.
- Mulch with wood chips or pea straw, keeping it clear of the trunk.
Watering and feeding
Water deeply once or twice a week in dry weather for trees in the ground, and two or three times a week for trees in pots. Water well while young, in long dry spells and as the fruit develops.
Citrus are gross feeders. Feed with a citrus fertiliser in spring and again in late summer or autumn, following the rate on the pack. Yellow leaves with green veins point to iron deficiency.
Pruning and care through the year
- Little pruning is needed beyond shaping and removing any shoots from the rootstock below the graft.
- In frosty areas, cover young trees with frost cloth on cold nights or move potted trees under cover.
- Check for scale, leaf miner and borer holes, and spray copper after petal fall in early summer to help prevent scab.
Harvesting
Cumquats ripen from mid winter, depending on the variety, and hang on the tree for weeks. Pick when fully orange, snipping them off with a short stalk.
They keep about a week on the bench and 2 to 3 weeks in the fridge.
Growing in pots
Cumquats are ideal in pots at least 40 cm wide, with good drainage and a quality potting mix. Keep the pot in full sun, water deeply two or three times a week in warm weather, and feed regularly with a liquid or slow-release citrus food. A pot can be moved to follow the sun or under cover in winter.
Using it
Eat cumquats whole off the tree, skin and all; the skin is often sweeter than the flesh. They are classic for marmalade, and are also candied, preserved in syrup or sliced into cakes and salads.
Companion planting
Keep the root zone mulched and free of grass and weeds, as citrus roots are shallow.
Good companions
- Comfrey Its leaves can be cut and laid as a mulch around the tree. Plant it where you want it, as it is hard to remove.
Pests and diseases
Cumquats have few problems, though citrus pests can build up, especially in warm areas.
Pests to watch for
- Scale Hard or soft scale-like insects on stems, pale leaves, poor growth and small, dry fruit.
- Lemon tree borer Small holes in branches with sawdust-like frass, and dieback.
- Leaf miner Silvery, winding trails in new leaves, which curl and distort.
- Guava moth Larvae tunnelling into fruit, mainly in the upper North Island.
- Caterpillars Leaves tightly rolled, and the surface of the fruit eaten.
- Thrips Silvering of leaves and fruit, with black specks.
Diseases to watch for
- Melanose Small, raised, dark brown specks on leaves and fruit, from dead twigs in the canopy. Prune out dead wood.
- Citrus scab Verrucosis: grey, scabby, wart-like growths on fruit or stems.
Common questions
What is the hardiest citrus for New Zealand?
The cumquat. It handles light frost better than other citrus and is the most reliable choice for colder districts such as Canterbury and the central North Island.
Can you eat cumquats whole?
Yes. Eat them skin and all; the skin is often sweeter than the tart flesh.
Can I grow a cumquat in a pot?
Yes, they are ideal in pots at least 40 cm wide. Water two or three times a week in warm weather and feed regularly.
When are cumquats ripe?
From mid winter, when they are fully orange. They hang on the tree for weeks.
Do I need two cumquat trees?
No. Citrus are self-fertile, so one tree will crop.
Why are my cumquat leaves yellow?
Often a lack of feeding or iron deficiency (yellow leaves with green veins). Feed with a citrus fertiliser in spring and late summer, and check the drainage.
Sources we checked: Yates NZ: How to grow cumquats; Yates NZ: Common problems of cumquats; Waimea Nurseries: Kumquat Meiwa; Waimea Nurseries: How to grow citrus; Waimea Nurseries: Preventing pests and diseases.