English Walnut

Juglans regia 'Carpathian'

tree

English or Persian walnut (Juglans regia) is a broad, round-headed shade tree, commonly 40 to 60 ft tall and wide, grown for thin-shelled nuts with a mild, sweet kernel - the walnut of the grocery store. Standard Persian types are tender, so home growers in colder regions plant the Carpathian strain, which survives roughly minus 10 to minus 20 F. It is a long-term tree: most walnuts begin bearing at 7 to 8 years and reach full production near 15, then crop for decades, a mature tree yielding 50 to 80 lbs of kernels. Like all walnuts it produces juglone in its roots, leaves, and hulls, a natural compound that stunts many garden plants, so it needs careful siting.

✅ Plant alongside

Good neighbors that attract beneficial insects or deter pests

• Currant: A juglone-tolerant fruiting shrub that does well in the partial shade near a walnut
• Black Raspberry: Tolerates walnut juglone better than most brambles and uses the edge ground
• Clover: A juglone-tolerant nitrogen-fixing groundcover for the open soil under a young tree

❌ Keep away from

🛡️ Pest & disease prevention

Proactive ways to stop trouble before it starts. Tap a name with an arrow for its full guide

• Walnut husk fly →

  Maggots tunnel the hulls and stain the shells; rake up and destroy fallen nuts and hulls promptly, and hang traps to time any sprays

• Thousand cankers disease →

  A walnut twig beetle spreads this often-fatal fungus; keep trees vigorous, do not move walnut firewood, and remove declining limbs

• Codling moth →

  The same pest as on apples bores into nuts; sanitation and pheromone traps reduce numbers

🌾 Harvest & storage

Walnuts ripen in autumn when the green hulls split and the nuts fall. Gather them several times a week, because nuts left on damp ground quickly mold and darken the kernel. Wear gloves - the hulls stain hands and clothing a deep brown. Remove the hulls at once, wash the nuts, then cure them in a single layer in a dry, airy, shaded spot for two to three weeks before storing in the shell. Shaking limbs with a padded pole speeds the drop.

🥗 Nutrition & benefits

Walnuts are a rich source of healthy oils, plant protein, and omega-3 fatty acids, eaten raw, toasted, or baked, and pressed for walnut oil. In the garden the tree is a fine shade and timber tree, but remember the juglone it releases: keep tomatoes, peppers, potatoes, blueberries, azaleas, and rhododendrons well outside the root zone, and compost the leaves separately rather than tilling them into beds.