Origin
Crataegus douglasii Lindl. var. douglasii, commonly known as Douglas Hawthorn or Black Hawthorn, is a plant species that belongs to the Rosaceae family. The plant is native to western North America and can be found growing in British Columbia, Alberta, Montana, Oregon, Washington, and California.
Common Names
The plant is commonly known as Douglas Hawthorn due to its origin and Black Hawthorn, which refers to its dark-colored bark.
Uses
Crataegus douglasii Lindl. var. douglasii has been used for medicinal purposes by Native American tribes. The bark and leaves of the plant contain chemical compounds that have been found to have cardiovascular benefits. The plant was also used to relieve sore throats and coughs. In modern times, the plant is used as an ornamental tree due to its attractive appearance.
General Appearance
The Crataegus douglasii Lindl. var. douglasii is a deciduous tree that can grow up to 15 meters tall. The tree has a dense crown with oval or elliptic-shaped leaves that are about 2 to 5 cm long. The leaves have a serrated margin and are dark green in color. The bark of the tree is blackish-brown and has a rough texture. The tree produces white or pink flowers that bloom in clusters during spring and early summer. The fruit of the tree is a small red or black berry that is edible but not widely consumed by humans due to its sour taste.
Light Requirements
Crataegus douglasii Lindl. var. douglasii generally prefers to grow in full sun, although it can tolerate some shade. In areas with very hot summers, it may benefit from some afternoon shade.
Temperature Requirements
This plant is native to western North America and is adapted to a range of temperatures. It can tolerate both cold winters and hot summers, but excessive heat or frost can damage the plant. The ideal temperature range for Crataegus douglasii Lindl. var. douglasii is between 60-80°F.
Soil Requirements
Crataegus douglasii Lindl. var. douglasii grows best in well-draining soils that are rich in organic matter. The soil should be slightly acidic, with a pH range of 5.5-6.5. This plant can also tolerate some drought, but it grows best in moist but not waterlogged soil. Additionally, it is important to note that this plant is sensitive to high levels of salt in the soil.
Cultivation methods
Crataegus douglasii Lindl. var. douglasii, commonly known as Douglas' hawthorn, is a hardy plant that grows well in USDA zones 5 to 9. Ideally, it should be planted in a well-draining soil that is rich in organic matter and slightly acidic. This plant prefers full sun exposure, but it can tolerate some shade. It can be propagated through seeds or hardwood cuttings. When planting, make sure to leave enough space between the plants as they can grow up to 20 feet tall and wide.
Watering needs
Douglas' hawthorn requires moderate watering during its growing season, which is usually from spring to fall. The soil should be kept moist but not waterlogged. Too much water can cause root rot, while too little water can cause the leaves to wilt and turn yellow. It is important to water the plant deeply, allowing the water to reach the root zone.
Fertilization
To promote healthy growth and blooming, fertilize the plant in early spring using a balanced fertilizer. Do not over-fertilize, as this can lead to excessive growth and reduced flowering. You can also add compost or well-rotted manure to the soil in fall to improve soil fertility and structure.
Pruning
Regular pruning is essential to keep the plant healthy and promote flowering. Prune the plant in late winter or early spring before the new growth starts. Remove dead, damaged, or diseased branches, and cut back any branches that cross or rub against each other. You can also shape the plant by cutting back the top of the plant or reducing the size of its lateral branches. However, avoid cutting back more than one-third of the plant, as this can weaken the plant and reduce flowering.
Propagation of Crataegus douglasii Lindl. var. douglasii
There are several methods commonly used to propagate Crataegus douglasii Lindl. var. douglasii, including seed propagation, cutting propagation, and grafting.
Seed propagation
Seeds of Crataegus douglasii Lindl. var. douglasii can be collected in autumn and sown immediately or stored over winter and sown in early spring. They can be sown in pots or directly in the ground. The seeds require stratification to break dormancy before sowing, which can be achieved by storing them in the refrigerator for several weeks. Germination can take several months and may be uneven.
Cutting propagation
Softwood and hardwood cuttings can both be used to propagate Crataegus douglasii Lindl. var. douglasii. Softwood cuttings should be taken in late spring or early summer, while hardwood cuttings should be taken in late autumn or early winter. Cuttings should be taken from healthy, disease-free plants and treated with rooting hormone before being planted in well-draining soil. Rooting can take several months and may be low in success rate.
Grafting
Grafting is commonly used to propagate cultivars or selected trees of Crataegus douglasii Lindl. var. douglasii that have desirable characteristics. The most common method is whip grafting, which involves cutting the scion and rootstock at an oblique angle and joining them together. The graft union should be protected and the grafted plant should be kept in a sheltered location until it has fully established.
Disease Management
The plant Crataegus douglasii Lindl. var. douglasii is susceptible to a variety of diseases that can affect its growth and appearance. Here are some common diseases and ways to manage them:
Fire Blight
Fire blight is a bacterial disease that infects the plant's blossoms, twigs and branches. To control this disease, the infected parts of the plant should be removed and destroyed. You should also avoid over-fertilizing the plant with nitrogen, as this can make it more susceptible to fire blight.
Rust
Rust is a fungal disease that can cause orange or yellow spots to form on the leaves of the plant. To manage rust, you should remove any infected leaves and dispose of them. You should also avoid watering the plant from above, as this can spread the spores of the fungus. Instead, water the plant at the base.
Powdery Mildew
Powdery mildew is a fungal disease that can cover the leaves of the plant with a powdery white substance. The affected leaves should be removed and disposed of. To prevent powdery mildew, you should avoid over-watering the plant and ensure that it has good air circulation around it.
Pest Management
The plant Crataegus douglasii Lindl. var. douglasii can also be affected by various pests. Here are some common pests and ways to manage them:
Aphids
Aphids are small, sap-sucking insects that can cause deformation and yellowing of the plant's leaves. To get rid of aphids, you can spray the plant with a strong jet of water or use insecticidal soap. You can also introduce predatory insects like ladybugs or lacewings to control the aphids.
Codling Moth
Codling moth larvae can damage the fruit of the plant. To control codling moth, you can use pheromone traps to trap the male moths and prevent them from mating. You can also use insecticidal sprays to kill the larvae. It is important to avoid using insecticides when the plant is in bloom, as this can harm bees and other pollinators.
Leaf Miners
Leaf miners are insect larvae that feed on the plant's leaves, leaving tunnels or trails on their surface. To get rid of leaf miners, you can remove and destroy the affected leaves. You can also use insecticidal sprays or introduce predatory insects like parasitic wasps to control the leaf miners.
