Origin
Quercus ×grandidentata Ewan (pro sp.) is a hybrid between Quercus dentata (Japanese oak) and Quercus macrocarpa (bur oak). Its origin is traced to natural hybridization between the two parent species that occur mostly in the northeastern United States.
Common names
The plant has various common names including big-tooth bur oak, spotted oak, and bur oak cross.
Uses
The plant is an ornamental tree used in landscaping because of its unique features. It is also grown for its strong wood, which is used in making furniture, tool handles, and flooring. The acorns produced by the tree are an important source of food for wildlife and used as animal feed if processed correctly.
General Appearance
Quercus ×grandidentata Ewan (pro sp.) exhibits the characteristics of its parent species, Japanese oak, and bur oak. The tree can grow up to 100 feet tall and has a broad crown with a diameter spanning 60-80 feet. Its leaves are large, 8-12 inches long, and distinctive because of the deep lobes, sharp bristle tips, and toothy edges. The bark is gray, scaly, and furrowed, with an irregular pattern. Its acorns are large, 1.5-2 inches long, and have a shallow cap that covers 1/3 of the nut.
Light Requirements
Quercus ×grandidentata Ewan (pro sp.) typically grows in full sun to partial shade conditions. It can tolerate some shade, but full sun is optimal for growth. This species prefers an open canopy with plenty of light.
Temperature Requirements
Quercus ×grandidentata Ewan (pro sp.) is a hardy species that can grow in a range of temperatures. It grows well in cool to warm temperatures, with an optimal range of 60-80°F (15.5-26.5°C). It can tolerate cold temperatures down to -40°F (-40°C) and can survive hot temperatures up to 100°F (38°C).
Soil Requirements
Quercus ×grandidentata Ewan (pro sp.) prefers well-draining soil that is slightly acidic to neutral with a pH range of 5.5-7.0. It grows well in moist, well-drained soils that are rich in organic matter. This species cannot tolerate extremely wet or dry soils, and it does not grow well in compacted or poorly-drained soils.
Cultivation Methods
Quercus ×grandidentata Ewan (pro sp.) is native to North America and can grow in a variety of climates, from temperate to cool. The plant prefers full sunlight but can tolerate partial shade. It thrives best in soils that are well-drained, slightly acidic, and rich in organic matter.
To cultivate Quercus ×grandidentata Ewan (pro sp.), select a planting site that receives ample sunlight and has fertile soil. Prior to planting, amend the soil by adding compost or other organic matter. Dig a hole twice as deep and wide as the root ball and bury the plant, ensuring that the top of the root ball is level with the soil surface. Water the plant thoroughly, and continue to keep the soil moist throughout the growing season.
Watering Needs
Quercus ×grandidentata Ewan (pro sp.) requires regular watering, especially during the first growing season. The plant prefers moist soils and may need to be watered once or twice a week, depending on the weather conditions.
To water the plant, apply water directly to the soil and avoid getting water on the leaves or stems. Water in the morning or evening to reduce water loss from evaporation and to reduce the risk of fungal diseases. Monitor the soil moisture level regularly, and adjust your watering schedule accordingly.
Fertilization
Quercus ×grandidentata Ewan (pro sp.) benefits from regular fertilization to promote healthy growth. Apply a balanced fertilizer in early spring before new growth appears, and again in late spring or early summer.
Follow the manufacturer's instructions, and apply the fertilizer evenly around the base of the plant. Water the plant thoroughly after fertilization to help distribute the nutrients. Avoid over-fertilizing, as this can result in leaf burn and can damage the roots.
Pruning
Pruning is not usually necessary for Quercus ×grandidentata Ewan (pro sp.) but can be done to maintain the shape of the plant or to remove dead or damaged branches.
If pruning is necessary, do so in late winter or early spring before new growth appears. Use clean, sharp pruning shears, and make cuts just above a bud or branch junction. Remove no more than one-third of the plant, as excessive pruning can stress the plant and affect its growth.
Propagation of Quercus ×grandidentata Ewan (pro sp.)
Quercus ×grandidentata Ewan (pro sp.) is a hybrid of Quercus alba and Quercus prinus. This plant can be propagated through various methods:
Seed Propagation
Seeds are the most common method for propagating Quercus ×grandidentata Ewan. Select healthy seedlings and sow them in the fall, either in nursery beds or container pots, and keep the soil moist. Germination will take place in the following spring. Container-grown seedlings should be transplanted into the field after their first growing season.
Cuttings Propagation
Quercus ×grandidentata Ewan can be propagated through stem cuttings. Softwood cuttings, taken in early summer, should be approximately 6 inches long and taken from the tips of branches. Cuttings should be treated with rooting hormone and rooted under mist or in a high humidity environment.
Grafting Propagation
Grafting is a propagation method that involves joining together a scion (the desired plant) with a rootstock of another plant. Quercus ×grandidentata Ewan can be propagated through grafting by budding or whip grafting.
Layering Propagation
Layering is the process of rooting a branch while it is still attached to the parent plant. Quercus ×grandidentata Ewan can be propagated through simple layering or air layering. Layering in the early spring or late summer often leads to successful propagation.
Disease Management
Quercus ×grandidentata Ewan is susceptible to various diseases, including oak wilt and leaf spots. Oak wilt is a fungal disease that affects the vascular system of the tree, leading to wilted and discolored leaves. The disease spreads through underground root networks, making it difficult to control. The best approach to oak wilt management is preventive measures like sterilizing pruning tools, avoiding wounds on the trees and proper disposal of diseased trees. In the case of leaf spots, the damage usually appears on leaves, and they manifest as tiny spots or as larger areas of dead tissue. The ideal way to manage leaf spots is to prune out the affected areas on the tree and adopting proper cultural practices such as ensuring proper drainage, avoiding overhead irrigation, and preventing overcrowding to reduce leaf wetness.
Pest Management
Quercus ×grandidentata Ewan is also affected by various pests, including gypsy moths, oak skeletonizers, and scales. Gypsy moths can cause significant defoliation, leading to reduced growth rates in trees. The most effective way to manage gypsy moths is by using chemical sprays that target only the larvae while sparing beneficial insects. Oak skeletonizer feeds on the underside of leaves, causing considerable damage to the plant. When the pest infestation is extreme, a chemical treatment may be necessary. Scales are tiny insects that attack the bark of oak trees, leading to a decline in the tree's health. To manage these pests, a combination of cultural and chemical controls may be adopted. The cultural controls include reducing stress on trees by providing water and nutrients, pruning infected areas and using resistant plant varieties. The chemical controls include the use of insecticidal sprays that target scales during the dormant season.
