Origin
Crataegus columbiana T.J. Howell var. occidentalis (Britt.) Dorn, commonly called western hawthorn, originates from North America, specifically from the west coast regions of the United States and Canada.
Common Names
Western hawthorn is also commonly known as the Douglas hawthorn, Columbia hawthorn, or the western thornapple.
Uses
The western hawthorn plant has several uses. It is widely used in horticulture as an ornamental tree or shrub, due to its attractive flowers and foliage. It is also sometimes used for wildlife habitat restoration and erosion control as it is a relatively hardy plant that can grow under various conditions.
In traditional medicine, the plant's leaves, flowers, and fruits are said to have therapeutic properties, such as aiding digestion, improving blood circulation, and reducing inflammation.
General Appearance
The western hawthorn is a deciduous shrub or small tree that usually grows to be around 5 to 10 meters tall. It has an attractive, dense, and round shape that makes it an excellent landscaping plant. The plant has lobed green leaves that turn into shades of orange, red, and purple in the fall.
During the spring season, it produces fragrant white or pink flowers that grow in clusters, which then become small red, black, or yellow fruits (haws) that are edible but often quite sour.
The branches of the western hawthorn are covered in sharp thorns that can grow up to 5 centimeters long, making it an effective natural barrier against trespassers or predators.
Light Requirements
Crataegus columbiana T.J. Howell var. occidentalis requires moderate to full sunlight for optimal growth. Inadequate light can result in stunted growth and reduced fruit production.
Temperature Requirements
This plant thrives in cool and temperate climates. It can tolerate a wide range of temperatures, between 0°C and 35°C. The plant can withstand occasional frost periods, but prolonged exposure to sub-zero temperatures can cause severe damage to the plant. The optimal temperature range for growth is between 18°C and 22°C.
Soil Requirements
The plant prefers well-draining soils with moderate to high levels of organic matter. It can grow in a wide range of soil types, including sandy, loamy, and clay soils. The ideal soil pH is between 6.0 to 7.5. The plant is tolerant of salty soils and can grow in areas with moderate soil salinity. However, it is sensitive to waterlogged soils and can develop root rot when grown in poorly drained soils.
Cultivation Methods
C. columbiana T.J. Howell var. occidentalis is mainly found in regions with moist soils, such as riparian zones, wetlands, or bog margins. Therefore, it is best grown in well-draining, moist soils with a pH of 6.1 to 7.8. A spot with partial shade is recommended over direct exposure to sunlight. The plant can tolerate temperatures from -28°C to 38°C.
Watering Needs
Watering is crucial when it comes to growing this plant. During the summer, it is recommended to keep the soil moist, but not waterlogged. Consistent watering in the first few years of growth is ideal for optimal establishment. During the dormancy period, the water supply can be reduced to prevent root rot.
Fertilization
C. columbiana T.J. Howell var. occidentalis can benefit from fertilization in the early stages of growth. You can add a slow-release, balanced fertilizer in the spring to provide nutrients gradually throughout the season. Ensure that the fertilizer is not placed directly near the roots to avoid burning them, and follow the manufacturer's instructions for application.
Pruning
The pruning of C. columbiana T.J. Howell var. occidentalis is not often necessary. However, you can remove dead or diseased wood at any time of the year. In the early spring, you can prune the plant to shape it and remove the previous year's growth. Avoid pruning late in the summer or fall, as new growth may not harden off before frost. Sterilizing pruning tools before and after use prevent the spread of diseases.
Propagation of Crataegus columbiana T.J. Howell var. occidentalis (Britt.) Dorn
Crataegus columbiana T.J. Howell var. occidentalis (Britt.) Dorn, commonly known as western thornapple, can be propagated by seeds, cuttings, layering, or grafting.
Seeds
The easiest and most common method of propagation is by seeds. The seeds of Crataegus columbiana T.J. Howell var. occidentalis (Britt.) Dorn can be collected in autumn when they have been fully ripened. The seeds should be sowed in a well-draining soil mix in a pot or directly into the ground where they are to grow. They should be covered with a thin layer of soil and kept moist. Germination will occur in spring.
Cuttings
Hardwood cuttings can be taken in winter by using a sharp, sterilized knife to remove a piece of stem no longer than 15 cm from the mother plant. The cuttings should be dipped in rooting hormone and planted in well-draining soil mix. They should be kept moist and placed in a warm, bright location, but out of direct sunlight. After several weeks to several months, the cuttings should develop roots.
Layering
Layering is a relatively simple propagation method. In mid-summer, identify a low-hanging branch on the mother plant that can be bent down to the ground. Make a small cut on the underside of the branch where it touches the soil and apply rooting hormone. Secure the branch to the ground with a U-shaped wire and cover the cut with soil. Roots should develop after a few months, at which point the new plant can be separated from the mother plant.
Grafting
Grafting is a more advanced propagation method and is typically used when it is necessary to maintain specific traits of the parent plant. It involves joining a piece of the desired plant (the scion) to a separate plant with a root system (the rootstock) that is closely related to the parent plant. This is typically done in late winter or early spring when the plant is dormant. The two plant parts are joined together using a grafting tape or wax and allowed to grow together for several months until they form a single plant.
Disease Management
Crataegus columbiana T.J. Howell var. occidentalis is prone to several diseases that can impact its health and yield. Some of the common diseases that affect this plant include:
- Cedar rust: This is a fungal disease that affects the fruit, leaves, and twigs of the plant. The symptoms of this disease include yellow spots on the leaves, brown spots on the fruit, and small, reddish-brown spots on the twigs. To manage this disease, it is advisable to plant resistant varieties, prune infected plant parts, and apply fungicides.
- Fire blight: This is a bacterial disease that affects the flowers, shoots, and leaves of the plant. The symptoms of this disease include wilting of plant parts, blackened shoots, and cankers. To manage this disease, it is advisable to prune and destroy infected plant parts, avoid overhead watering, and apply copper-based fungicides.
- Powdery mildew: This is a fungal disease that affects the leaves, shoots, and flowers of the plant. The symptoms of this disease include powdery white coating on the leaves, stunted growth, and distorted leaves. To manage this disease, it is advisable to plant resistant varieties, improve air circulation, and apply fungicides.
Pest Management
Crataegus columbiana T.J. Howell var. occidentalis is also prone to several pests that can damage the plant. Some of the common pests that affect this plant include:
- Aphids: These are small insects that suck sap from the leaves and stems of the plant. The symptoms of aphid damage include yellowed leaves, stunted growth, and distorted leaves. To manage this pest, it is advisable to release natural predators such as ladybugs, lacewings, and parasitic wasps, prune and destroy heavily infested plant parts, and apply insecticidal soap.
- Caterpillars: These are the larvae of moths and butterflies that feed on the leaves and fruit of the plant. The symptoms of caterpillar damage include chewed leaves, defoliation, and damaged fruit. To manage this pest, it is advisable to handpick and destroy caterpillars, use Bacillus thuringiensis (Bt) insecticides, and release natural predators such as birds and parasitic wasps.
- Scale insects: These are small, immobile insects that suck sap from the leaves and stems of the plant. The symptoms of scale insect damage include yellowed leaves, stunted growth, and distorted leaves. To manage this pest, it is advisable to prune and destroy heavily infested plant parts, apply horticultural oil, and release natural predators such as parasitic wasps.
