The large oddly named "English" walnut tree, which is actually native to central Asia, is a beautiful and useful tree for its aesthetics and food-growing abilities alike. It is a great tree to grow if you have the room and are looking to add a specimen or shade tree. The nuts of Juglans regia are much easier to harvest than those of Juglans nigra (the black walnut) as they fall without the husk and can be gathered with a garden rake and eaten raw or used in cooking.
If you have the room and the sun, it requires you may want to put the English Walnut on your list of trees to consider growing.
|Common Name||English Walnut|
|Botanical Name||Juglans regia|
|Plant Type||Deciduous Tree|
|Mature Size||40-60 ft. tall, 40-60 ft. wide|
|Sun Exposure||Full Sun|
|Soil Type||moist, organically rich, well-drained|
|Bloom Time||May to June|
|Hardiness Zones||USDA 3-7|
|Native Area||Europe to Central Asia|
English Walnut Care
For being such an amazing tree, the English walnut is incredibly low maintenance. Providing sufficient care will ensure that your tree is healthy and supplies you with the most amount of nuts to harvest when the time comes. Just performing these few maintenance chores, like planning a watering routine, knowing when and how to harvest, and knowing the best way to fertilize, will keep you and your tree happy for decades to come.
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, you need to plant your tree 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.
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.
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 so as to not wet 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.
Once established, it is a good idea to 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.
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 of 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’ - slow-growing tree with abundant fruiting potential and long flowering season to offset frost damage risk.
- Juglans regia 'Chandler' - 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 your English walnut should be done annually in the winter to at first establish a strong single leader and rounded crown structure with good lateral branching that will allow for 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.
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 method here it is in five easy steps:
- Collect walnuts after they fall.
- 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.
- 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 fill sand and peat mix with a few spritzes of water to moisten the mix and putting 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.
- After stratification, plant the nut two inches deep and wait for it to germinate.
- Care for the sapling and wait eight years to collect your first harvest of walnuts.
Common Pests and 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.
Are English walnut trees allelopathic?
Although the English walnut produces juglone, the same compound that the black walnut produces to cause the allelopathic affect it is produced in a much lower concentration.
Are there dwarf forms of English walnut?
There are a number of cultivars but the miniscule Juglans regia 'Europa' tops out at only six feet or so.
Why is Juglans regia called English walnut?
In other countries and other places around the world it is called other things. That is why the best thing to call any plant is always its scientific name, in this case Juglans regia. Consider it like a universal language.