Quercus ×rehderi Trel.
Quercus ×rehderi Trel. is a hybrid cross between Quercus mongolica Fisch. and Quercus dentata Thunb. It belongs to the Fagaceae family and is native in Japan, Korea, and China. It was named after Alfred Rehder, a German-American botanist who specialized in trees.
Common Names
Quercus ×rehderi Trel. is commonly known as Rehder oak, Korean oak, or Japanese Emperor oak. In Japan, it is called the "taiwan shii" while in Korea, it is known as the "namsiju".
Appearance
The Rehder oak is a deciduous tree that can grow up to a height of 25 meters. Its leaves are dark green, glossy, and oval in shape; they grow up to 20 cm long and 15 cm wide. The leaves have smooth edges and can be slightly serrated near their tips. During autumn, the leaves turn a beautiful shade of yellow before falling off the tree. The bark of the tree is dark brown, rough, and fissured. The tree produces acorns that measure up to 2 cm in length and are enclosed in a cup called a "cupule". The cupule can be oval or rounded in shape and covered in small scales.
Uses
Quercus ×rehderi Trel. is primarily used as an ornamental tree in parks and gardens due to its attractive foliage and habit. Its leaves are also used for making tea, which is said to have medicinal benefits. The wood of the Rehder oak is strong and durable, making it suitable for use in furniture, flooring, and construction. The acorns are also used as a food source for wildlife.
Growth Conditions for Quercus ×rehderi Trel.
Quercus ×rehderi Trel., commonly known as Rehder oak, is a hybrid tree that combines the qualities of the two parent species - Quercus robur and Quercus bicolor. This deciduous tree grows up to 20-30 meters tall with a broad and rounded crown and sturdy trunk.
Light Requirements
Quercus ×rehderi Trel. prefers full sun exposure to partial shade for optimal growth. It can grow in light shade, but the growth rate will be slower, and the tree may become leggy and weak.
Temperature Requirements
Rehder oak is adaptable to a wide range of temperatures, but it grows best in cool temperate climates. The ideal temperature range for the growth of Quercus ×rehderi Trel. is between 10°C and 24°C (50°F to 75°F). The tree is also cold-hardy and can withstand winter temperatures as low as -35°C (-31°F).
Soil Requirements
Quercus ×rehderi Trel. prefers well-drained, loamy soils that are nutrient-rich with a pH level between 4.5 and 6.5, although it can tolerate a slightly higher pH. The tree also prefers soil that is moderately moist but not waterlogged or dry. It can grow in a wide range of soils, including clay, sandy loam, and rocky soils, as long as they are well-drained.
Cultivation Method for Quercus ×rehderi Trel.
Quercus ×rehderi Trel. is a hardy plant that can be grown in various climatic conditions. It is important to choose the right site for planting this tree. The best place to plant the tree is in well-draining soil with plenty of organic matter. The plant should be exposed to at least 6 hours of sunlight daily. The tree can be propagated using seeds or cuttings.
Watering Needs for Quercus ×rehderi Trel.
Quercus ×rehderi Trel. requires regular watering, but the soil should not be too wet. The plant should be watered deeply at least once a week, especially during the hotter months. However, care should be taken not to overwater the tree as this can cause root rot and other diseases. A good tip is to water the tree early in the morning or late in the afternoon.
Fertilization for Quercus ×rehderi Trel.
Quercus ×rehderi Trel. requires regular fertilization to grow properly. The tree should be fertilized in the early spring and late fall. An all-purpose fertilizer that has a balanced mixture of nitrogen, phosphorus, and potassium should be used. The amount of fertilizer to be used will depend on the age and size of the tree. A good rule of thumb is to fertilize the tree with 1 lb of fertilizer per inch of trunk diameter, up to a maximum of 20 lbs per year.
Pruning for Quercus ×rehderi Trel.
Regular pruning is essential for the proper growth of Quercus ×rehderi Trel. The tree should be pruned in late winter or early spring when the tree is dormant. Dead or diseased branches should be removed immediately, and any branches growing towards the center of the tree should be pruned. The central leader should be maintained to ensure a healthy shape. It is also important to prune the tree to maintain a balance between foliage and fruit.
Propagation of Quercus ×rehderi Trel.
Quercus ×rehderi Trel. commonly known as Rehder Oak is propagated by seeds, layering, and grafting.
Seed Propagation
Quercus ×rehderi Trel. can be propagated by sowing its acorns. The acorns are collected during the autumn season, as soon as they fall from the tree. The acorns are soaked in water for a day or two to remove any residual germination inhibitors and to promote germination. The acorns are then planted in well-prepared soil in a nursery bed, with their pointed ends just below the soil surface. The seedlings may take up to six months to germinate. After two to three years, the seedlings can be transplanted to their permanent site.
Layering
Layering is a vegetative propagation method of Quercus ×rehderi Trel. In this process, a low branch of the parent tree is Pegged to the ground and covered with soil. The branch is allowed to grow roots at the flag where the bark has been scraped off and is kept moist by watering or by a regular rainfall. When the rooted stem is ready to form a tree, it is separated from the parent plant by being cut from the stem. The layers can also be left on the parent plant to form a more extensive root system before transplanting.
Grafting
Grafting is a vegetative propagation method employed in Quercus ×rehderi Trel. The grafting is typically done in late winter before the new growth begins. A stem section containing a bud, called a scion, is taken from the desired plant, usually in early winter. The scion is then grafted onto a closely related rootstock. The rooted cutting is then grown in a nursery bed until it is large enough to be transplanted into the field.
Disease and Pest Management for Quercus ×rehderi Trel.
Quercus ×rehderi Trel., also known as Rehder oak, is a hybrid plant resulting from the cross between Quercus cerris and Quercus robur. As with most plants, Rehder oak is susceptible to various diseases and pests. However, there are ways to manage these problems and protect the plant's health.
Common Diseases
One of the most common diseases that affect Rehder oak is powdery mildew. This fungus causes a white or gray powdery coating on the leaves, which can eventually lead to leaf drop. To manage powdery mildew, prune the affected branches and destroy them. Additionally, ensure that the plant has adequate air circulation and avoid overhead watering.
Anthracnose is another fungal disease that can affect Rehder oak, which causes brown spots on the leaves and can lead to defoliation. To manage anthracnose, prune and destroy affected branches, avoid overhead watering, and use fungicides if necessary.
Common Pests
One of the most common pests that affect Rehder oak is the oak leaf roller. These caterpillars feed on the leaves, causing defoliation. To manage oak leaf rollers, prune and destroy affected branches and use insecticides if necessary.
Another pest that can affect Rehder oak is the oak lace bug. These bugs suck the sap from the leaves, causing them to turn yellow or brown. To manage oak lace bugs, use insecticidal soap or horticultural oils. Additionally, ensure that the plant has adequate nutrients and water.
Preventive Measures
One of the best ways to manage diseases and pests on Rehder oak is to prevent them from occurring in the first place. Ensure that the plant receives adequate sunlight and water, as well as proper fertilization. Keep the plant pruned to promote air circulation, and avoid overhead watering. Finally, keep an eye on the plant for signs of problems and address them promptly.
By following these disease and pest management practices, you can help ensure the health and longevity of your Quercus ×rehderi Trel.
