Crataegus L.: A Comprehensive Description
Crataegus L. also known as Hawthorn, a widespread genus of thorny shrubs and small trees in the family Rosaceae. The genus is native to temperate regions of the Northern Hemisphere.
Common Names
The plant is popularly known as hawthorn, maythorn, thornapple, or mayflower. The name hawthorn is derived from the Old English term "hagathorn" which means hedge thorn.
Appearance
Crataegus L. generally grows to about five feet and commonly found in woodlands, scrub, and hedge-rows. The leaves are simple, lobed or coarsely toothed, and arranged alternately on slender branches with thorny edges. The flowers are white or pink and usually have five petals. They grow in clusters, known as corymbs, and bloom in late spring to early summer. The fruits are small pomes, which resemble miniature apples, and turn red or black when ripened.
Uses
The plant has numerous medicinal uses and has been used by many cultures for centuries. For example, the ancient Greeks employed hawthorn to treat heart disorders, while the Chinese utilized it to promote digestion. Hawthorn contains flavonoids, tannins, and antioxidants which help improve circulation, reduce blood pressure, and boost cardiovascular health. The fruits and leaves of hawthorn are also used to make teas, syrups, and tinctures. In addition, the plant is widely cultivated for ornamental purposes as well as for use as a rootstock for grafting pear trees and for making bonsais.
Light Requirements
The Crataegus L. plant typically requires full sun to partial shade for optimal growth. It can tolerate some shade, but the growth and bloom may be affected. The more sun exposure it gets, the healthier and stronger it will grow. Therefore, it is best to plant it in a spot that receives at least six hours of sunlight.
Temperature Requirements
The Crataegus L. plant is quite hardy when it comes to temperature requirements. It can tolerate both hot summers and cold winters, but the optimal temperature range for its growth is between 15 to 30°C. It can easily withstand frost and sub-zero temperatures but may struggle in excessively hot temperatures.
Soil Requirements
The Crataegus L. plant needs well-draining soil to thrive. It prefers slightly acidic to neutral soil pH levels, ranging from 5.5 to 7.5. The plant requires moist soil, but it cannot survive in water-logged soils that may cause root rot. The soil should be rich in organic matter, and adding compost or aged manure can help improve soil fertility.
Cultivation Methods
Crataegus L. is relatively easy to cultivate and maintain. The plant thrives in well-drained soils that are fertile and rich in organic matter. The ideal pH range of the soil is between 6.0 to 7.5. The plant requires moderate sunlight exposure and can be grown in both partial shade and full sun. It is advisable to propagate the plant using seedlings, cuttings, or grafting. Planting should be done during the spring or fall seasons when the soil is warm and moist.
Watering Needs
Crataegus L. requires regular watering, especially during the first few weeks after planting. Newly planted saplings should be watered two to three times a week in the absence of rainfall. The frequency of watering can be reduced to once a week once the plant is established. The soil should be kept moist but not waterlogged, and proper drainage should be ensured to prevent waterlogging.
Fertilization
The plant requires a balanced fertilizer that is rich in nitrogen and potassium. Fertilization should be done during the growing season, which is spring and summer. The fertilizer should be applied to the soil around the plant to ensure that it reaches the roots. The application rate depends on the size of the plant and should be done according to the manufacturer's instructions.
Pruning
Pruning is essential in maintaining the health and shape of the Crataegus L. plant. It is advisable to prune the plant during the dormant season, which is in late winter. The plant should be pruned to remove dead or diseased branches, as well as to thin out dense growth and improve air circulation. It is also recommended to prune the plant to create a desirable shape or size. Pruning should be done using sterile pruning shears to prevent the spread of diseases.
Propagation of Crataegus L.
Crataegus L. can be propagated through both sexual and asexual propagation methods.
Sexual Propagation
Seeds are the primary means of sexual propagation for Crataegus L. The seeds should be collected in the fall or winter and stored properly until they are ready for sowing. To improve germination rates, the seeds should go through stratification, a process of exposing them to cold, moist conditions that help break dormancy. Seeds can be sown either in containers or directly in the ground in the spring. However, it should be noted that seedling-grown Crataegus L. may not resemble the parent plant.
Asexual Propagation
Asexual propagation methods for Crataegus L. include grafting and softwood cuttings.
Grafting involves attaching a section of the desired Crataegus L. variety to a rootstock of a related tree. The procedure involves making a cut on the rootstock and the shoot to be grafted and then physically joining the two plant parts. The joined sections are then bound together with tape or grafting wax until the graft union has formed.
Softwood cuttings should be taken from the parent plant in the late spring or early summer. The cuttings should be 4-6 inches long with a few leaves and should have a diameter no larger than a pencil. The leaves should be removed from the bottom half of the cutting, and the cutting should be treated with a rooting hormone before being planted in a mixture of sand and peat moss. The cuttings should be kept moist and in a warm, bright location until roots have developed.
Disease and Pest Management for Crataegus L.
Crataegus L., commonly known as hawthorn, is susceptible to several diseases and pests that can affect its growth and production. Here are some of the most common issues that hawthorn plants can face:
Diseases
Cedar Rust: Cedar rust is a fungal disease that can cause hawthorn leaves to turn yellow and drop prematurely. The disease is caused by a fungus that first infects juniper trees and then spreads to hawthorns. To manage cedar rust, it is advisable to remove any nearby juniper plants and spray the hawthorn with a fungicide.
Fire Blight: Fire blight is a bacterial disease that can cause hawthorn branches to wilt and turn black. The disease spreads through the plant's vascular system and can kill the entire plant if not managed quickly. To manage fire blight, the affected branches should be pruned and removed, and the plant should be sprayed with an antibacterial spray.
Powdery Mildew: Powdery mildew is a fungal disease that can cause a white, powdery coating to form on hawthorn leaves. The disease can stunt plant growth and reduce fruit production. To manage powdery mildew, it is advisable to improve air circulation and spray the plant with a fungicide.
Pests
Aphids: Aphids are sap-sucking insects that can cause hawthorn leaves to curl and distort. The insects secrete a sticky substance called honeydew that attracts ants and promotes the growth of black sooty mold. To manage aphids, the plant should be sprayed with a pesticide or a strong jet of water can be used to dislodge them.
Scale Insects: Scale insects are small, immobile pests that attach themselves to the plant's stems and leaves. They suck the sap from the plant, causing yellowing and leaf drop. To manage scale insects, the plant should be sprayed with an insecticide, and the affected leaves should be pruned and removed.
Regular inspection and monitoring of hawthorn plants can help detect and manage any disease or pest issues early. Early intervention is crucial in preventing the spread of diseases and the damage caused by pests.
