How to grow Walnut in Australia
The English walnut (Juglans regia) is a large, long-lived deciduous tree for cool districts with cold winters, such as Tasmania, the tablelands, inland Victoria and the Adelaide Hills. Grafted trees start bearing within a few years and reach full production after a decade or more, then crop for many years. It needs deep soil and a great deal of room.
📖 Our full guide: How to Grow Walnut in Australia
At a glance
When to plant by region
| Region | When to plant | Regional note |
|---|---|---|
| South East Queensland | Not suited | Not viable in SEQ. Walnuts need a cold dormant winter the coast never gets. |
| Northern Rivers NSW | Not suited | Not viable. Walnuts need cold winters that even the Lismore and Kyogle hinterland does not deliver. |
| Sydney & Coastal NSW | June to August | Cold western gardens and the mountains only; the coast lacks winter chill. A very large tree. Plant bare root Jun to Aug. |
| Melbourne & Victoria | June to August | |
| Adelaide & SA | June to August | |
| Perth & WA | June to August | |
| Tasmania | June to August | |
| Canberra & ACT | June to August | |
| North Queensland | Not suited | Not viable. Walnuts need a cold dormant winter. Impossible on the tropical coast. |
| Darwin & Top End | Not suited | Not viable. Walnuts need a cold dormant winter. Darwin has none. |
Where to plant
Walnuts need full sun, cold winters and long, warm summers, and deep, rich, well-drained soil. They are big trees, 15 m or more tall and wide, so plant well away from buildings, drains and other plants, and plan for the size the tree will be in ten or twenty years.
Walnut roots and leaves release juglone, a natural compound that holds back the growth of many plants beneath and near the tree, so do not plan a vegie patch or orchard under it.
- Hobart, Canberra, Melbourne and Adelaide: plant bare-rooted trees from June to August. The cooler hills and tablelands suit them best.
- Perth: plant from June to August in the cooler hills; check that your variety suits a mild winter.
- Sydney: only in the cold western areas and the mountains; the coast lacks winter chill.
- South East Queensland, the Northern Rivers, North Queensland and Darwin: not suited, as walnuts need a cold, dormant winter.
Choosing a variety
Buy grafted trees of named varieties from a specialist nursery; seedling walnuts are slow and variable. Walnut flowers often release pollen at a different time from when the female flowers are receptive, so planting two compatible varieties improves cross-pollination and cropping. Varieties that leaf out late are less likely to be caught by spring frost.
How to plant
- Plant bare-rooted trees in winter while they are dormant.
- Dig a wide hole in deep, well-drained soil improved with organic matter. Do not plant in heavy, waterlogged ground.
- Spread the roots, plant at the same depth the tree grew in the nursery, and keep the graft above soil level.
- Water in deeply and mulch about 10 cm thick over the root area, keeping mulch off the trunk.
- Stake young trees in windy sites.
Watering and feeding
Water deeply once or twice a week in dry weather, especially from bud burst in spring through nut filling in summer. Young trees need regular water for their first few years.
Feed twice a year, in early spring and late summer, with a complete fertiliser, and keep a thick organic mulch over the root zone.
Pruning and care through the year
- Prune young trees in their dormant season to form a strong framework with a central leader or a few well-spaced main branches. Mature trees need only occasional pruning, every three or four years, to remove dead, crossing or low branches.
- Avoid pruning in late winter and early spring when the sap is rising, as walnuts bleed heavily from cuts then.
- Protect young growth from late frosts where you can, and choose late-leafing varieties in frosty sites.
Harvesting
Walnuts ripen in autumn, around April and May. The green husks split open and the nuts drop. Collect them from the ground every few days so they do not go mouldy or get taken by birds and rodents, and remove any husk still attached (wear gloves, as the husk stains hands dark brown).
Wash and dry the nuts in a single layer somewhere warm and airy for a few weeks, until the kernel snaps rather than bends. Store dry nuts in the shell in a cool, dry place for months; shelled kernels freeze well.
Using it
Eat walnuts fresh, or use them in baking, salads, pesto and with cheese. Green, unripe walnuts picked in early summer are used to make pickled walnuts and nocino liqueur. Walnuts can cause serious allergic reactions in some people.
Companion planting
Walnuts do not make good neighbours. Juglone from the roots and leaves holds back many plants, and the trees cast heavy shade.
Keep apart
Avoid planting these close to walnut.
Pests and diseases
Walnut blight and codling moth are the main problems in Australian home orchards, along with birds and rodents at harvest.
Pests to watch for
- Codling moth Caterpillars tunnelling into the nuts, which drop early. Clear up fallen nuts.
- Birds Nuts opened or taken from the tree as husks split. Collect fallen nuts promptly.
Diseases to watch for
- Walnut blight Black spots on leaves and young shoots and black, sunken patches on the green husks, in wet, mild spring weather. Affected nuts drop or have dark kernels.
- Anthracnose Brown leaf spots and early leaf drop in wet summers.
Common questions
Can I grow a walnut tree in my backyard?
Only if you have plenty of room and a cool climate. Walnuts grow 15 m or more tall and wide, need cold winters and deep soil, and their juglone holds back plants growing nearby.
How long does a walnut tree take to produce nuts?
Grafted modern varieties may bear a few nuts within their first few years, produce a useful crop at about four to six years, and reach full production at about ten to twelve years.
Do I need two walnut trees?
It helps. Walnut trees often shed pollen at a different time from when their own female flowers are ready, so two compatible varieties give better pollination and bigger crops.
When are walnuts ready to harvest?
In autumn, about April and May, when the green husks split and the nuts fall. Collect them every few days and dry them well before storing.
Can I grow vegetables under a walnut tree?
Not well. Walnuts release juglone, which holds back many plants, especially tomatoes, and the trees cast heavy shade. Keep vegie beds well away from the roots.
Can walnuts grow in Queensland?
No. Walnuts need a cold, dormant winter, so they are not suited to South East Queensland, the Northern Rivers or the tropics.
Sources we checked: Yates: How to grow walnuts; Wikipedia: Juglans regia.