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Fruits, Nuts & Perennial Crop CalendarsWalnut Calendar
Walnuts leaf out late, bloom with the leaves and drop nuts in fall. English and black walnuts differ in climate fit, and both have quirks that affect where you plant them.
Key points
- Pick a walnut type that fits your winters.
- Juglone limits what you can grow near the tree.
- Gather nuts promptly and dry them well.
- Check quarantine rules before moving wood or nuts.
What are the main walnut types?
English walnuts, also called Persian walnuts, are the familiar commercial nut and suit milder climates, with some cold-hardy selections. Black walnuts are native to much of the eastern United States and are hardier, with a strong flavor and a very hard shell. Butternuts and heartnuts are related species with their own needs.
Choose the type that fits your winters and your goal. Ask extension which walnut types and varieties do well in your area, since climate and disease pressure differ widely.
If you only want a shade tree that happens to drop nuts, black walnut is a fine choice in suitable climates, but keep in mind the cleanup and the stain from husks.
Why does site choice matter so much for walnuts?
Walnuts, especially black walnut, release a compound called juglone that can harm some nearby plants, including tomatoes and several others. Extension offices publish lists of plants that tolerate or suffer near walnuts. Plan your garden layout before you plant.
Walnuts also grow into large trees and need deep, well drained soil and plenty of room. Do not plant near buildings, septic systems or power lines, and consider how big the tree will be in decades.
Late spring frost can damage new leaves and flowers, so avoid low frost pockets.
- Keep juglone-sensitive plants away from the root zone
- Give trees deep, well drained soil
- Allow for a very large mature size
When do walnuts leaf out and bloom?
Walnuts leaf out relatively late in spring, which reduces frost exposure compared with early fruit trees. Male catkins and female flowers appear on the same tree, and wind carries pollen. Timing of the two can differ, so some varieties pollinate better with a second tree.
Check pollination notes for your variety. Keep notes of when your tree leafs out each year, since a warm spring shifts the schedule.
A late frost after leaf-out can burn new growth and reduce the crop, even though walnuts leaf later than most. Planting on ground that drains cold air lowers the risk.
How do you care for walnuts through summer?
Young trees need regular watering for the first few years, with mulch to hold moisture and cut weed competition. Established trees tolerate dry spells but nut size suffers in drought.
Feed according to a soil test and local advice. Nutrient management rules vary by state. Prune young trees to establish a strong central structure, and avoid heavy pruning on mature trees, which may bleed sap if cut at the wrong time.
Watch for dry spells during nut fill in late summer, when water stress shrinks kernels. Deep, infrequent watering of young trees builds a stronger root system than light daily sprinkling.
When are walnuts ready to harvest?
Walnuts mature in fall. The green husk splits and loosens, and nuts begin to drop. Gathering nuts promptly after they fall reduces damage from moisture, insects and squirrels. Black walnut husks stain hands and surfaces, so wear gloves.
Remove husks soon after harvest, wash nuts and dry them in a ventilated place to protect quality. Properly dried nuts store much better than damp ones.
Keep a nutcracker, a bucket and a pair of gloves near the tree in fall. Gathering a few times a week is far easier than a big cleanup after weeks of rain and squirrels.
How should you cure and store walnuts?
Drying brings nuts to a safe moisture level before storage. Spread them in a single layer with air movement, and avoid heat sources that cook the kernel. Check extension guidance for storage and shelling, and for food safety practices if you sell nuts.
Do not store nuts in sealed containers while damp. Mold can produce harmful compounds, and any nuts that smell musty or show mold should be discarded.
Test a few nuts by cracking them. A kernel that snaps rather than bends is usually dry enough, though your extension office can suggest a better test for your variety.
What pests and diseases affect walnuts?
Walnut husk fly, codling moth, blight, anthracnose and thousand cankers disease are among the concerns, depending on region. Some are subject to quarantine, so contact your state department of agriculture before moving wood or nuts.
This guide gives no product names or rates. Follow your extension guide, use only labeled products as directed, observe pre-harvest intervals and protect pollinators.
Sources and further reading
Last reviewed: November 2026. Educational information, ranges only. Confirm timing with your county extension office.