English Walnut Care
Juglans regia
A valuable tree grown for its nuts. Although less so than Black Walnut, it can harm some plants through the 'juglone' compound released from its roots (allelopathy). A productive harvest requires deep, well-drained soil and regular care.
Hardy · -25 °C / -13 °F
Monthly care calendar
Timings are for a temperate Northern Hemisphere climate. In warmer areas tasks start earlier, in colder areas later; in the Southern Hemisphere shift them by six months.
January
- Plant protection: Whitewashing tree trunks with lime in the winter months can prevent frost cracks and some pests.
- Pests & diseases: Check the trunk and branches. Frost protection is not needed.
February
- Pruning: While the tree is in full dormancy, perform formative pruning on young trees to establish the main scaffold branches. On mature trees, only remove dead, diseased, water sprouts and crossing branches to open up the canopy.
- Plant protection: After pruning, apply graft sealant to thick branches. This is a suitable time to apply Bordeaux mixture.
March
- Watering: Water a newly planted specimen more often than established plants during its first year, as its root system is still shallow.
- Fertilizing: Apply a balanced fertilizer or well-rotted organic fertilizer once when it wakes from dormancy. Because yield and fruit quality depend on nutrient balance, having a soil analysis done is especially useful for this plant.
- Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
- General care: Good time for planting and transplanting.
- Pests & diseases: Check the branches and trunk for brown, fixed bumps (scale insects).
April
- Watering: If there is no rainfall, water every 15 days.
- Plant protection: Monitor for aphids and diseases such as anthracnose.
- General care: Flowering begins.
- Pests & diseases: Prepare to manage codling moth (apple and walnut fruit moth).
May
- Watering: If there is no rainfall, water once a week.
- Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
- General care: Flowering continues. Spread mulch 5-7 cm thick over the root zone; it conserves soil moisture and suppresses weeds. Do not pile mulch against the trunk.
- Pests & diseases: If you see black spots with yellow halos on the leaves (black spot), collect the diseased leaves and remove them from the garden; the disease overwinters in fallen leaves. Check the branches and trunk for brown, immobile bumps (scale insects).
June
- Watering: Water deeply twice a week; prefer infrequent and generous watering over small and frequent. The root zone should be wetted to a depth of 30-40 cm.
- Pruning: Do shaping and hedge pruning. Light form pruning is enough; cutting the branches in late fall reduces the risk of sap bleeding. Avoid heavy structural pruning; the cuts heal slowly.
- Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
- Pests & diseases: If you see black spots with yellow halos on the leaves (black spot), collect the diseased leaves and remove them from the garden; the disease overwinters in fallen leaves.
July
- Watering: Water deeply twice a week; prefer infrequent and generous watering over small and frequent. The root zone should be wetted to a depth of 30-40 cm.
- Plant protection: Check for walnut husk fly.
- General care: Continue watering.
- Pests & diseases: Hot and dry weather can increase the risk of spider mites.
August
- Watering: Water deeply twice a week; prefer infrequent and generous watering over small and frequent. The root zone should be wetted to a depth of 30-40 cm.
- General care: Kernel filling in the fruit is completed.
September
- Watering: If there is no rainfall, water once a week.
- Pruning: Do the last formative pruning of the season; do not let it put out new shoots before frost.
- Plant protection: If symptoms spread and treatment is needed, consult a licensed plant-protection supplier or an agronomist. Plant protection products are regulated; follow local rules.
- General care: To harvest, shake the tree or strike it with a pole. Collect walnuts that fall to the ground immediately.
- Pests & diseases: If you see black spots with yellow halos on the leaves (black spot), collect the diseased leaves and remove them from the garden; the disease overwinters in fallen leaves.
October
- Watering: If there is no rainfall, water every 15 days. Water newly planted plants more often than established plants during the first year; the root system is still shallow.
- Fertilizing: After harvest, a phosphorus- and potassium-heavy fertilizer (e.g. 5-15-30 NPK) can be applied for next year's yield.
- General care: Good time for planting and transplanting.
- Pests & diseases: Collect fallen leaves and fruit husks to prevent diseases from carrying over to the next year.
November
- Watering: Water a newly planted specimen more often than established plants during its first year, as its root system is still shallow.
- General care: Good time for planting and transplanting. Collect fallen leaves; many disease agents and pests overwinter under them.
December
- General care: The tree goes fully dormant.
- Pests & diseases: Check the trunk and branches.
The care advice on this page is general and for information only; it is not professional advice. Plant age, soil and your garden’s microclimate can change the outcome. Plant protection products are mentioned only as general information; they are regulated, and the choice, dose and timing must be decided by a qualified professional under local rules. Consult a landscape architect or agronomist before applying.
Want reminders for every plant in your garden? Our garden-care app with monthly task lists and frost alerts is currently available in Turkish; the English version is on the way.
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