How to Grow and Care for English Walnut

The large, oddly-named English walnut tree (Juglans regia), which is actually native to central Asia, is a beautiful and useful tree for its aesthetics, shady canopy, and food-growing abilities alike. The English walnut is incredibly low maintenance, just avoid hot weather and humid climates and aim for full sun. Read on for our full care and growing guide.

Common Name	English Walnut
Botanical Name	Juglans regia
Family	Juglandaceae
Plant Type	Tree
Mature Size	40-60 ft. tall, 40-60 ft. wide
Sun Exposure	Full
Soil Type	Moist, well-drained
Soil pH	Acidic
Bloom Time	Spring
Flower Color	Yellow, green
Hardiness Zones	3-7 (USDA)
Native Area	Asia

English Walnut Care

Here are the main care requirements for an English walnut tree:

• This tree requires full sun
• Water newly-planted trees weekly through spring and summer
• Fertilize in the spring
  

Light

The English walnut does not demand much, but full sun is on its list of must-haves. For your tree to thrive and produce a prolific amount of walnuts, plant it in an area that receives at least six hours of direct sun a day. You will notice some deficits in production and growth if your walnut tree is not given ample light.

Soil

The English walnut is a big tree, and it will require deep soil to support its root system, which grows very deep. That deep soil should also be fertile and full of plenty of organics while still draining adequately. The tree prefers a pH range of 6.0 to 6.5.

Water

Your newly planted English walnut tree needs to be watered weekly throughout the spring and summer of the first two growing seasons of its life using a soaker hose to avoid wetting the foliage. Use the standard of two to three gallons of water per diameter inch of trunk, measured by caliper at chest height. Be sure to release the water slowly so that it penetrates deep into the soil without running off. Slow release watering bags, which extend watering for hours, can assist with this. Once established, taper your irrigation off to a biweekly schedule, using a straight diameter instead of a caliper measurement.

Temperature and Humidity

Avoid hot and humid weather and climates; the English Walnut prefers the cooler climates associated with USDA zones 3-7.

Fertilizer

Give your tree a regular boost of fertilizer in the spring. Using a slow-release, high-nitrogen fertilizer with ammonium sulfate will help keep your plant growing vigorously through the growing season. For the amount to use, follow product label instructions.

Types of English Walnut Trees

There are many cultivars of English walnut trees currently available, and more are being developed yearly. Each cultivar is specifically selected for a unique trait that makes it superior to the straight species. As English walnut is such a predominant food crop, most of these traits are developed to highlight needs in crop production, such as frost hardiness or nut production. The cultivars that highlight one trait are often placed on the rootstock of another cultivar or species to capture that host plant's more favorable trait. Some examples of well-known cultivars are:

• Juglans regia ‘Caspian’ leafs out late to help avoid late-spring frosts.
• Juglans regia '‘Chaldoran’ has medium vigor and high fruit-bearing potential which offsets the risks of late-frost damage.
• Juglans regia ‘Alvand’ is a slow-growing tree with abundant fruiting potential and long flowering season to offset frost damage risk.
• Juglans regia 'Chandler' is a cultivar developed at the University of California at Davis that is highly productive with medium-large, plump, light-colored kernels that have outstanding taste. One of the most popular cultivars available.

Pruning

Pruning your English walnut should be done annually in the winter to establish a strong single leader and rounded crown structure with good lateral branching. This will allow plenty of room for your walnuts to grow. When doing these cuts, it is important to look for any weak, dead, or damaged branches and remove them. Eventually, your tree will outpace your ability to make safe cuts with either a handsaw or a pole saw, and it will be best to call in a licensed arborist to do the work for you. Remember never to use a chain saw from a ladder.

Propagation

It is easy to grow English walnuts from seed if you follow a few simple steps, but the easiest way to grow a walnut tree and fastest way to produce a harvest is by buying a young tree. If you still want to try the seed propagation method here it is in five easy steps:

1. Collect walnuts after they fall.
2. Remove the hulls and then place the nuts in a glass of water. Nuts that float are not viable and can be thrown away (or eaten). Good, viable nuts will sink to the bottom of the glass.
3. The viable walnuts will need to stratify (i.e., be exposed to cold and moist conditions that mimic winter conditions underground). Stratification can be done by placing the nuts in a sandwich bag filled with a moist sand and peat mix. Put the bag in the veggie drawer in your fridge for 90-120 days. Alternatively, you can plant the nuts directly in the ground in the fall for a less controlled result.
4. After stratification, remove each nut and plant it two inches deep and wait for it to germinate.
5. Care for the sapling and plant in the landscape when it reaches a sturdy size. Wait about eight years to collect your first harvest of walnuts.

Common Pests & Plant Diseases

Walnut husk fly is the pest that is of most concern in regards to English walnuts. Fly larvae feed on walnut hulls and make their removal difficult. The walnuts will still be edible but less desirable as a food crop. To combat this pest, place landscape fabric under the tree canopy in late summer to prevent larvae from entering the soil. Additionally, remove all nuts that fall to the ground. Sprays labeled for homeowner use to control walnut husk fly can be used, but be sure to consult the labels for exact instructions and warnings.

The most serious disease for English walnuts is thousand cankers; the disease is caused by a fungus that the walnut twig beetle spreads. The disease is named thousand cankers due to the number of cankers that can occur in a single tree. Symptoms will include yellowing and thinning of foliage in the upper crown, branches dying off, wilting foliage, and eventually tree death. Once infected and symptoms appear, a tree will die in three years or so.

From: thespruce