Origin and Common Names
Crataegus oxyacantha L. var. paulii (Rehd.) Rehd. is a plant that belongs to the Rosaceae family and is commonly known as Paul's hawthorn. It is native to China where it grows wild in open fields and forest edges. Due to its ornamental value and medicinal properties, it has been introduced and cultivated in many countries around the world.
General Appearance
Paul's hawthorn is a deciduous shrub or small tree that can grow up to 6 meters in height. It has a dense, bushy crown and a rounded shape. Its branches are covered in short, sharp thorns that make it difficult to handle. The leaves are simple, lobed, and serrated, with an oval shape and a dark green color. The flowers are white or pink, and they bloom in springtime. The fruit is a small, red, berry-like pome that can persist on the plant throughout the winter.
Uses
Paul's hawthorn has been used in traditional Chinese medicine for centuries to treat a wide range of ailments. Its leaves, flowers, and fruits are rich in flavonoids, triterpenoids, and other biologically active compounds that have antioxidant, hypotensive, and vasodilatory effects. It is commonly used to improve heart function, alleviate chest pain, reduce blood pressure, and prevent cardiovascular disease. It is also used to treat digestive disorders, skin disorders, and anxiety. In addition to its medicinal properties, it is also a popular ornamental plant that is prized for its beautiful flowers and colorful fruits.
Light Requirements
Crataegus oxyacantha L. var. paulii (Rehd.) Rehd. is a sun-loving plant and requires at least 6 hours of direct sunlight daily. Lack of sunlight causes stunted growth and reduces flower and fruit production.
Temperature Requirements
The plant grows best in areas with a moderate climate. The ideal temperature range for Crataegus oxyacantha L. var. paulii (Rehd.) Rehd. is between 10°C to 25°C (50°F to 77°F). It can also survive in slightly colder areas and can withstand temperatures as low as -20°C (-4°F) in its dormant state.
Soil Requirements
Crataegus oxyacantha L. var. paulii (Rehd.) Rehd. grows well in well-drained soil rich in organic matter. The soil should be acidic to slightly alkaline with a pH range of 6.0 to 7.5. The plant is moderately drought tolerant, but regular watering is essential during the growing season. It is also important to avoid waterlogging as it can cause root rot and damage the plant's health.
Cultivation methods
Crataegus oxyacantha L. var. paulii (Rehd.) Rehd. is a hardy shrub that can grow in a wide range of soils. It prefers well-draining soil that is slightly acidic with a pH of 6 to 7.5. This shrub can tolerate full sun to partial shade.
To cultivate Crataegus oxyacantha L. var. paulii (Rehd.) Rehd., start by selecting a suitable location with well-draining soil. Dig a hole twice the size of the root ball and backfill with a mixture of compost and soil. Water the plant thoroughly after planting.
This shrub can also be propagated through seeds or cuttings. To propagate through seeds, sow in early spring in a seed tray and place in a sunny location. For cuttings, take softwood cuttings in early summer and root in a moist growing medium.
Watering needs
Crataegus oxyacantha L. var. paulii (Rehd.) Rehd. requires moderate watering. It needs frequent watering during the first year after planting to establish its root system. Once established, reduce watering but ensure the soil does not dry out completely. Overwatering can lead to root rot.
During dry spells, water the shrub more frequently and deeply. Avoid watering the leaves to minimize the risk of fungal diseases.
Fertilization
Crataegus oxyacantha L. var. paulii (Rehd.) Rehd. benefits from fertilization during the growing season. Use a balanced fertilizer with equal amounts of nitrogen, phosphorus, and potassium. Apply the fertilizer once a month between April and September.
Avoid over-fertilization as this can lead to excessive foliage at the expense of flowers. Too much fertilizer can weaken the plant's resistance to pests and diseases.
Pruning
Pruning is essential to shape Crataegus oxyacantha L. var. paulii (Rehd.) Rehd. and to maintain its health. It is best to prune during the dormant season in late winter or early spring.
To prune, remove any dead or diseased wood. Cut back any crossing branches to prevent rubbing and injuries. Thin out any old or weak stems to allow more air and light into the plant. Be sure to sterilize your pruning tools with alcohol to prevent the spread of diseases.
Propagation of Crataegus oxyacantha L. var. paulii (Rehd.) Rehd.
Crataegus oxyacantha L. var. paulii (Rehd.) Rehd. can be propagated through several methods:
Seed Propagation
Seed propagation is a common method for propagating Crataegus oxyacantha L. var. paulii (Rehd.) Rehd. The seeds are collected when mature, typically in the fall. Before sowing, the seeds are stratified for three months. Stratification helps to break the seed dormancy and encourages germination. After stratification, the seeds can be sown in a well-draining soil mix. The seeds should be kept moist and warm in a bright, sheltered location. Germination typically occurs within 20 to 30 days.
Cuttings Propagation
Crataegus oxyacantha L. var. paulii (Rehd.) Rehd. can also be propagated through stem cuttings. Hardwood cuttings should be taken during the dormant season and softwood cuttings in early summer. The cuttings should be taken from healthy and disease-free plants. The cuttings should be prepared by removing the leaves and dipping the basal end in rooting hormone. The cuttings should be planted in a well-draining soil mix and kept moist in a bright, sheltered location. Rooting typically occurs within 6 to 8 weeks.
Grafting Propagation
Grafting is another method for propagating Crataegus oxyacantha L. var. paulii (Rehd.) Rehd. The rootstock is typically a vigorous, disease-resistant species of hawthorn, while the scion is taken from a desired cultivar. The grafting should be done during the dormant season. The success of grafting depends on proper technique and healthy materials.
Disease Management
The plant Crataegus oxyacantha L. var. paulii (Rehd.) Rehd. is susceptible to several diseases that can affect its health and growth. Some common diseases that may affect this plant include:
- Fabraea leaf spot: This disease is caused by a fungus that produces dark, circular spots on the leaves. The spots may expand and coalesce, causing the leaves to yellow and drop prematurely. To manage this disease, remove and destroy infected plant debris and practice proper sanitation measures, such as cleaning tools and equipment between uses.
- Fire blight: This bacterial disease causes leaves, flowers, and shoots to wilt and turn black, giving the plant a scorched appearance. To manage fire blight, prune infected plant parts at least 12 inches below the visible symptoms and disinfect pruning tools with rubbing alcohol or bleach between cuts.
- Cedar apple rust: This fungal disease produces yellow-orange spots on the leaves and causes premature defoliation. It also affects the fruit, producing brown, scabby lesions. To manage cedar apple rust, remove any juniper plants in the area and avoid planting susceptible apple varieties near juniper trees.
Pest Management
In addition to diseases, the plant Crataegus oxyacantha L. var. paulii (Rehd.) Rehd. is also susceptible to several pests that can damage the plant. Some common pests that may affect this plant include:
- Aphids: These small, soft-bodied insects suck sap from the leaves and stems, causing distorted growth and yellowing. To manage aphids, spray the plant with a strong jet of water to dislodge the insects, or use insecticidal soap or neem oil.
- Eastern tent caterpillars: These hairy caterpillars form communal webs on the branches and defoliate the plant. To manage eastern tent caterpillars, remove and destroy the webs by pruning the affected branches or manually removing the caterpillars.
- Japanese beetles: These beetles feed on the leaves and flowers, skeletonizing them and causing severe damage. To manage Japanese beetles, handpick them off the plant in the early morning when they are sluggish, or use insecticidal sprays or traps.
