Walnut Tree

A large deciduous tree producing edible nuts, but its roots release juglone which inhibits many nearby plants including tomatoes, apples, and blueberries. Plant walnut trees well away from vegetable gardens and sensitive ornamentals, giving them the wide spacing their massive mature canopy requires. Trees take seven to ten years to begin bearing, but once productive they can yield over a hundred pounds of nuts annually for decades. Harvest walnuts when the green husks begin to split and dry the shelled nuts thoroughly before storage to prevent mold.

Named walnut varieties are propagated by grafting onto seedling walnut rootstock. Patch budding in summer or whip grafting in spring are the most common techniques. English walnut scions are often grafted onto black walnut or Paradox hybrid rootstock for improved vigor and disease resistance. Seeds require 90 to 120 days of cold stratification and produce variable seedlings that take 7 to 10 years to bear. Plant stratified seeds in deep containers to accommodate the taproot. Purchase grafted trees for guaranteed variety and earlier production.

The Season Plate

Your Walnut Tree Year

Composed for Zone 7 · typical seasons · frost passes Apr 2, returns Nov 1

Sow Walnut Tree Mar – Apr, Nov, pick Sep – Oct. Set your climate below and every date on this plate re-times itself.

Sowing window

Mar – Apr, Nov

re-timed to your frost dates

Plant out

after Apr 2

once frost risk has passed

First picking

around Mar 13

≈ 2555 days from sowing · 30-70 kg per plant

Composed for —ColdTemperateMildWarmUse my locationUsed once to set your season · only the zone is kept

Week-by-week Walnut Tree reminders watering, feeding and pruning, timed to your dates

In the app

Frost alerts for your garden a warning before a cold night costs you the crop

In the app

Succession sowing dates so the picking never gaps mid-season

In the app

Keep my dates — free for 7 daysWe nudge you as each window opens · cancel anytime

Walnut trees are majestic, long-lived deciduous trees that can reach 50 to 75 feet tall with an equally wide canopy. Plant in full sun in deep, well-drained, fertile loam with a pH of 6.0 to 7.5. Walnuts develop a deep taproot and extensive lateral root system, so choose a permanent location with ample space. Space trees 40 to 60 feet apart. The most critical consideration is juglone toxicity: walnut roots, leaves, and hulls release juglone, a compound that inhibits or kills many garden plants including tomatoes, peppers, blueberries, and apples.

Water young walnut trees deeply once a week during the first 3 to 5 years to encourage deep root development. Established trees are moderately drought-tolerant but produce better nut crops with supplemental irrigation during dry summers. Apply a balanced fertilizer in early spring, spreading it beneath the drip line. Zinc deficiency is common in walnut trees and causes rosetting of terminal leaves; apply zinc sulfate foliar sprays when symptoms appear.

Prune walnut trees in late summer or early fall rather than in winter or spring, as fresh pruning wounds in wet conditions are susceptible to walnut blight. Train young trees to a central leader with well-spaced scaffold branches. Remove lower limbs gradually as the tree grows to provide clearance beneath the canopy. English walnuts generally require a pollinizer variety within 100 feet for best nut production, though some cultivars are partially self-fertile.

Due to juglone toxicity, companion planting around walnut trees requires careful plant selection. Juglone-tolerant plants include black raspberries, elderberries, currants, and some stone fruits. Tolerant perennials include hostas, daylilies, black-eyed Susans, and most spring bulbs. White clover, Kentucky bluegrass, and fescue grasses tolerate juglone for ground cover. Keep walnut trees at least 50 feet from vegetable gardens, tomatoes, peppers, and blueberries, which are extremely sensitive to juglone.

The Society Table

Black-eyed Susan belongs beside it. Tomato doesn't.

Old growers' knowledge, checked against Walnut Tree's real companion table below — test any plant you're growing.

Grows well in the company of · 2

Black-eyed SusanConeflower

Keep apart · 2

TomatoApple Tree

Plant Walnut Tree with good neighboursThe planner flags conflicts before they're in the ground

Walnut trees require deep, well-drained, fertile loam with a pH of 6.0 to 7.5 for best production. They do not tolerate waterlogged conditions or shallow soil over hardpan. Apply a balanced fertilizer in early spring at a rate of 1 to 2 pounds per inch of trunk diameter, spread beneath the drip line. Zinc is the most commonly deficient micronutrient in walnuts; apply zinc sulfate as a foliar spray at budbreak if leaves show rosetting or interveinal chlorosis. Avoid excessive nitrogen that promotes blight-susceptible soft growth.

Ideal Temperature

Hardiness Zone Compatibility

Walnuts are ready to harvest in September and October when the green outer husk begins to split and darken. Shake or knock branches to dislodge ripe nuts, or collect them from the ground daily to prevent mold development. Remove the husks immediately after harvest, wearing gloves as the husk juice stains skin and clothing dark brown. Wash the shelled nuts and dry them thoroughly in a warm, well-ventilated area for 2 to 3 weeks before storage to prevent mold inside the shell.

Storage & Preservation

Properly dried walnuts in the shell keep at room temperature for 2 to 3 months and in the refrigerator for up to a year. Shelled walnut kernels store best in airtight containers in the freezer for up to 2 years, as the high oil content causes rancidity at warm temperatures. Toast walnuts lightly to extend shelf life and enhance flavor. Green walnuts harvested in June can be pickled whole in vinegar and spices, a traditional English condiment. Walnut oil pressed from fresh kernels is a prized culinary ingredient.

Troubleshooting Common Problems

Juglone toxicity from walnut roots kills or damages many common garden plants, limiting what can be grown within the root zone that extends well beyond the canopy drip line. This is the most important factor to consider before planting. Walnut blight during wet springs can devastate nut crops. Late spring frosts damage early-leafing varieties; choose late-leafing cultivars for frost-prone sites. Squirrels are aggressive nut thieves that can harvest an entire crop before the grower. Large mature trees are difficult to prune and maintain safely.

Growing Tips

1. Select a planting site with full sun exposure and deep, well-drained loamy soil. Walnut trees develop extensive taproots and lateral root systems, so avoid sites with shallow bedrock, high water tables, or compacted clay subsoil that restricts root penetration below 1.5 meters.
2. Purchase grafted named cultivars rather than seedling trees for reliable nut quality and earlier bearing. Popular home garden varieties include Chandler for high-quality large nuts, Franquette for late leafing that avoids spring frost, and Broadview for colder climates with a self-fertile tendency.
3. Be aware of juglone toxicity when planning your garden layout. Walnut roots, leaves, and husks release juglone which is toxic to many plants including tomatoes, peppers, potatoes, azaleas, and apple trees. Keep susceptible plants at least 15-20 meters from the walnut canopy drip line.
4. Prune walnut trees only during full winter dormancy from December through February, as they bleed sap heavily from pruning wounds made during active growth. Focus on establishing a strong central leader with 4-6 well-spaced scaffold branches at wide crotch angles to support heavy nut crops.
5. Apply zinc sulfate as a foliar spray in spring if leaves show interveinal chlorosis or rosetting of terminal growth. Zinc deficiency is the most common micronutrient problem in walnut trees worldwide and significantly reduces nut yield and quality if left uncorrected.
6. Water deeply and consistently during the growing season, providing 50-75 mm of water per week from fruit set through kernel fill. Use drip irrigation or flood irrigation rather than overhead sprinklers, as wet foliage promotes walnut blight caused by the bacterium Xanthomonas arboricola pv. juglandis.
7. Protect young trees from late spring frosts, which can destroy emerging flowers and shoot growth. Late-leafing cultivars like Franquette and Fernette are preferable in frost-prone areas, as they delay bud break until the risk of damaging frost has passed.
8. Harvest walnuts promptly when husks begin to split and nuts drop from the tree. Spread tarps beneath the canopy and shake branches with a long pole to dislodge ripe nuts. Remove husks within 24 hours and wash shells immediately to prevent tannin staining and mold development on the kernel surface.
9. Dry harvested walnuts thoroughly before storage by spreading them in a single layer in a warm, well-ventilated area for 2-3 weeks. Test dryness by cracking a sample nut and bending the kernel, which should snap cleanly rather than flex. Store dried walnuts in-shell in mesh bags in a cool, dark location at 1-4°C for up to a year, or freeze shelled kernels for up to two years.
10. Plant a second walnut variety within 30 meters for reliable cross-pollination if your chosen cultivar is strongly dichogamous. While English walnuts are monoecious with both male and female flowers on the same tree, many cultivars shed pollen before or after their own female flowers are receptive, reducing self-pollination success.