Overview
Juglans ×intermedia Carr. is a hybrid plant that belongs to the Juglandaceae family. This deciduous tree is the result of a cross between two species: Juglans nigra (black walnut) and Juglans regia (English or Persian walnut).
Common Names
This hybrid tree has several common names, including Cordiform hybrid walnut, Buckley walnut, Bastard walnut, and English black walnut.
Origin
Juglans ×intermedia Carr. originated in the United States, where it was first officially recorded in 1903. It was found growing in a nursery in Buckley, Washington and was believed to be the result of natural hybridization between black walnut and English walnut. This hybrid plant was later introduced to other regions and countries around the world.
Appearance
As a hybrid plant, Juglans ×intermedia Carr. has characteristics that are intermediate between its parent species. It is a medium-sized tree that can reach a height of 50-70 feet and a spread of 30-50 feet. It has a straight trunk and a broad, rounded canopy. The leaves are pinnate, 12-24 inches long, with 9-19 leaflets that have serrated edges. The bark is grayish-brown and deeply furrowed.
Uses
Juglans ×intermedia Carr. has similar uses to its parent species. The wood of this hybrid tree is prized for its strength and durability, and it is used for furniture, flooring, and cabinetry. The nuts are edible and have a similar flavor to that of black walnuts. They are used in baking and cooking, and are also a popular snack. The tree also has ornamental value, and is planted for its attractive foliage and shade.
Light requirements
Juglans ×intermedia Carr. requires full sun exposure to thrive. It can tolerate some shade, but it may not produce high-quality nuts if grown in low-light conditions. Therefore, planting it in an area with full access to sunlight is essential for its growth.
Temperature requirements
Juglans ×intermedia Carr. is a deciduous tree that grows best in temperate climates. It is sensitive to frost and requires a minimum of 120 frost-free days to develop properly. The growing season should have warm temperatures averaging at 15-27°C (60-80°F) to promote growth, flowering and production of viable nuts. Temperatures above 37°C (100°F) can cause stress and affect the quality of nuts.
Soil requirements
The plant grows best in well-drained, fertile soils with a slightly acidic to neutral pH range between 6.0 and 7.0. It also requires a depth of 1.2-1.8 meters (4-6 feet) to allow root expansion. It is essential to have adequate soil moisture since dry soil can lead to slower growth and nut production. However, wet soil can lead to root rot, which affects the tree’s overall health and can eventually cause its death. Adding organic matter, compost, and fertilizers during planting can provide the necessary nutrients that the tree needs to grow and produce high-quality nuts.
Cultivation of Juglans ×intermedia Carr.
Juglans ×intermedia Carr., commonly known as the Buartnut tree, is a hybrid between the Juglans ailantifolia (Japanese walnut) and the Juglans cinerea (Butternut). The plant is widely cultivated for its high-quality, nutritious nuts, which are larger and sweeter than those of its parents. To successfully cultivate Juglans ×intermedia, you should adhere to the following guidelines:
Watering needs
Juglans ×intermedia thrives in deep, well-drained soil and prefers moist but not wet conditions. During the growing season, the plant requires significant amounts of water to support healthy growth, fruit production, and nut quality. It is best to provide the plant with regular, deep watering rather than shallow and frequent watering that could lead to root rot. Irrigation should be reduced in the fall to allow the tree to harden off before the winter.
Fertilization
Adequate fertilization is crucial for the optimal growth and nut production of Juglans ×intermedia. A soil test is necessary to determine the plant's nutrient requirements accurately. A well-drained and fertile soil enriched with organic matter is ideal. Nitrogen, phosphorus, potassium, and other minor elements are essential for the tree's growth and development. Mature trees require yearly top dressing of compost and mulch applications to conserve moisture and soil nutrients.
Pruning
Pruning is vital to maintain a healthy, productive, and well-shaped Juglans ×intermedia tree. The ideal time to prune the plant is during the dormant season in late winter or early spring before new growth commences. Weak branches, dead or diseased wood, and suckers should be removed to reduce shading and redirect energy to more productive parts of the tree. Mature trees require thinning to enhance nut production and light penetration. Young trees should be trained to one central leader and scaffold trees to promote a strong framework.
Propagation of Juglans ×intermedia Carr.
Juglans ×intermedia Carr. is commonly propagated by using grafting and budding techniques that involve combining the rootstock of one plant with the scion of another plant. These techniques are used to obtain plants that exhibit desirable traits, such as disease resistance or improved yield.
Grafting
Grafting is a common technique used for propagating Juglans ×intermedia Carr. plants. In this method, a portion of the scion plant, which contains the desired traits, is grafted onto the rootstock of another plant, which provides the roots and stem. The plants are then bound together until they grow into a single plant.
Grafting requires specific tools and techniques to ensure a successful graft. Proper sanitation is necessary to prevent the spread of diseases and pests, and the right timing is crucial to ensure that the graft union forms properly.
Budding
Budding is another technique used for propagating Juglans ×intermedia Carr. This method involves taking a small bud from the scion plant and inserting it into a small incision made in the rootstock plant. The bud is then secured in place until it grows into a new shoot.
Budding requires less skill and equipment than grafting, but it has a lower success rate. It is best performed in the spring or summer when the bark of the rootstock plant is slipping.
Overall, both grafting and budding are effective methods for propagating Juglans ×intermedia Carr. plants. However, they both require proper timing, equipment, and technique to ensure a successful propagation.
Disease and Pest Management for Juglans ×intermedia Carr.
Juglans ×intermedia Carr., commonly known as Heartnut, is a hybrid of Butternut and Japanese Walnut. Like other plants, Juglans ×intermedia Carr. is also prone to diseases and pests. Here are some of the common diseases and pests that can affect the plant and ways to manage them.
Diseases
1. Thousand Cankers Disease: This disease is caused by a fungus that attacks the tree's bark, creating small cankers on the trunk and branches. The disease can cause branch dieback, leaf yellowing, and premature defoliation. To manage Thousand Cankers Disease, prune and dispose of infested branches and avoid moving firewood, as the disease can spread through the wood. Fungicide applications may also be helpful.
2. Black Pecan Aphids: These tiny insects can cause leaf curling, yellowing, and stunted growth in Heartnuts. The aphids secrete a sticky substance called honeydew, which can attract ants and other pests. To manage black pecan aphids, apply insecticidal soap or neem oil directly onto the infested areas and encourage natural predators such as ladybugs and lacewings.
Pests
1. Walnut Caterpillars: These caterpillars can cause severe defoliation of Heartnut trees, making them susceptible to other pests and diseases. To manage walnut caterpillars, prune and destroy egg masses, apply Bacillus thuringiensis (BT) spray onto the foliage, and encourage natural predators such as birds and wasps.
2. Walnut Husk Fly: Walnut Husk Fly can damage Juglans ×intermedia Carr.'s fruit by laying eggs on the developing husks. The larvae then feed on the nuts' outer layer, causing them to rot and drop prematurely. To manage the Walnut Husk Fly, remove any damaged husks as soon as possible, apply traps to capture adult flies, and use insecticides when necessary.
Overall, implementing good cultural practices such as adequate irrigation, fertilization, and sanitation can help prevent the onset of diseases and pests in Juglans ×intermedia Carr. Regular monitoring of the plants can also help detect any issues early, allowing for timely management.
