Overview of Rhamnus uhligii Engl.
Rhamnus uhligii Engl. is a plant species that is commonly known as Uhlig's Buckthorn. It is a part of the Rhamnaceae family and is endemic to the Eastern Arc Mountains of Tanzania. This shrub species thrives in submontane and montane forests at altitudes between 1400 to 2100 metres above sea level. The plant is named after the Tanzania-based German botanist, Ernst Uhlig, who extensively researched plants in the Eastern Arc Mountains.
Appearance of Rhamnus uhligii Engl.
Rhamnus uhligii Engl. is a slow-growing, deciduous shrub that can reach up to five metres in height. It has a compact, bushy habit with branched stems and thorns. The leaves are simple, alternate and elongated-oval-shaped with a smooth margin and a glossy dark green colour that can turn yellowish in autumn. The plant flowers between March and September, producing small greenish-yellow flowers that bloom in clusters at the base of the leaves. The flower gives rise to a small berry with a single seed, which ranges in colour from green to black.
Uses of Rhamnus uhligii Engl.
The bark from the Rhamnus uhligii Engl. shrub is traditionally used by communities living in the Eastern Arc Mountains to heal wounds, cure gonorrhoea, and as a painkiller. The bark extract is also believed to have strong antibacterial properties, which make it useful in treating skin infections. Additionally, the plant's leaves and twigs are an important food source for the Eastern Arc Mountains' fauna, including birds and primates.
Rhamnus uhligii Engl. has several potential benefits that make it an exciting prospect for research. In 2019, a study found that the plant contains biologically active compounds that exhibit anti-tumour properties, which could be developed into cancer-fighting drugs. Furthermore, the shrub's ability to absorb heavy metals such as lead and cadmium could make it a useful tool for phytoremediation, which is the process of using plants to clean up contaminated sites.
In conclusion, Rhamnus uhligii Engl. is an intriguing plant species that is endemic to the Eastern Arc Mountains in Tanzania. Its traditional medicinal uses, relevance to wildlife, and potential for research make it a valuable species to the local community and the wider world.
Growth conditions for Rhamnus uhligii Engl.
Rhamnus uhligii Engl. is a small tree that grows in rocky areas and crevices in mountainous regions. It is native to Tanzania, where it can be found in the Uluguru Mountains at elevations between 1500 and 2200 meters above sea level.
Light
Rhamnus uhligii Engl. prefers partial shade to full sun exposure. The plant can be grown in areas that receive dappled light or full sun provided that the soil is kept moist during the growing season. If grown in too much shade, the plant may become spindly and weak.
Temperature
The ideal temperature range for Rhamnus uhligii Engl. is between 15°C and 25°C. The plant can tolerate temperatures as low as 5°C and as high as 30°C, but it may suffer frost damage or heat stress when exposed to extreme temperatures for prolonged periods of time.
Soil requirements
Rhamnus uhligii Engl. prefers well-draining soil that is rich in organic matter. The soil should have a pH level between 5.5 and 7.5. The plant can grow in various types of soil, including loam, sandy loam, and rocky soil. However, it does not tolerate waterlogging or stagnant water, so the soil should never be allowed to become waterlogged.
It is also important to note that Rhamnus uhligii Engl. is adapted to rocky areas and crevices, so it can tolerate shallow, poor soils with low fertility. However, in order to promote healthy growth and flowering, it is recommended to amend the soil with organic matter and well-balanced fertilizer.
Cultivation of Rhamnus Uhligii Engl.
Rhamnus uhligii Engl. is an evergreen plant that can thrive in various soil types. It can be propagated through seeds or cuttings.
For seed propagation, sow the seeds in a mixture of peat moss and perlite with a depth of around 1/4 inch. Keep the soil moist and provide bottom heat until germination occurs.
For cutting propagation, use semi-hardwood cuttings of around 4-6 inches in length. Dip the cut end into rooting hormone and plant them in a well-draining soil mix. Cover with plastic to increase humidity and place in a bright, indirect light area until roots form.
When planting in the ground, make sure to choose a location with well-draining soil and partial shade to avoid subjecting the plant to direct sunlight.
The ideal planting time is in the spring or early fall, when the soil is warm but not overly dry.
Watering Needs of Rhamnus Uhligii Engl.
Rhamnus uhligii Engl. needs regular watering, particularly during dry spells or hot summer months. However, it is important to avoid waterlogging the soil.
Allow the soil to dry slightly before watering thoroughly. In an outdoor setting, it is crucial to use a soaker hose to water the plant at the base rather than overhead watering, as this can cause fungal diseases.
Fertilization of Rhamnus Uhligii Engl.
Apply a balanced fertilizer once a year during the growing season. An organic slow-release fertilizer may be preferable, such as compost or manure. Avoid over-fertilizing, as this can lead to excessive leaf growth and poor fruiting.
Pruning of Rhamnus Uhligii Engl.
To encourage bushy growth and maintain the desired shape, prune Rhamnus uhligii Engl. in the late winter or early spring before new growth begins.
Remove any damaged, diseased, or dead wood along with any crossing branches or suckers. Afterward, trim back up to a third of the plant's overall growth.
Regular pruning can continue throughout the growing season to remove any diseased or damaged growth and to shape the plant.
Propagation Methods for Rhamnus uhligii Engl.
Propagation of Rhamnus uhligii Engl. can be done through seeds or cuttings.
Propagation by Seeds
The seeds of Rhamnus uhligii Engl. can be collected from mature fruits. The fruits are usually harvested in the fall when they have turned a dark hue. After harvesting the fruit, it should be opened to remove the seeds. The seeds must be cleaned and dried in a shaded area. After drying, they can be stored in an airtight container until ready for planting.
The best time to plant the seeds is in the spring. Before planting, the seeds must be soaked in water for 24 hours to facilitate germination. After soaking, the seeds can be sowed in a well-draining soil mix. The seeds must be kept moist and the soil should be kept warm. Germination usually takes between 30 to 90 days.
Propagation by Cuttings
Rhamnus uhligii Engl. can be propagated by woody stem cuttings. The branches must be collected during the dormant season, usually in the fall or winter. They must be at least 10cm long and have at least four nodes. The cuttings can be dipped in rooting hormone powder to improve rooting ability before planting.
The cuttings can be planted in a sterile, well-draining soil mix in a greenhouse or under a misting system. The leaves on the lower half of the cutting should be removed to stimulate root development. The cuttings should be kept moist and the temperature should be kept between 20-25°C. Rooting usually takes between six to eight weeks.
Disease and Pest Management for Rhamnus uhligii Engl.
Rhamnus uhligii Engl., commonly known as Uhlig's Buckthorn, is a small to medium-sized shrub that is native to Tanzania. While this plant is generally low maintenance and relatively pest and disease-resistant, it is still vulnerable to a few common issues that can affect its growth and overall health. Effective disease and pest management strategies can help to mitigate these issues and promote the long-term success of Rhamnus uhligii.
Common Diseases
One of the most common diseases to affect Rhamnus uhligii is Powdery Mildew.1 Symptoms of this disease include white or gray powdery growth on the leaves and stems of the plant, which can lead to stunted growth and eventual leaf drop. Powdery Mildew is often caused by high humidity and poor air circulation, so ensuring proper ventilation and avoiding overhead watering can help to prevent its spread.2 A fungicide applied at the first sign of infection can also help to control the disease and protect the plant.
Another potential disease to look out for is Black Spot.3 This fungal infection causes black or brown spots to appear on the leaves of the plant, which can lead to defoliation if left untreated. Like Powdery Mildew, Black Spot is often caused by humid conditions, so proper air circulation and regular watering can help to prevent its onset. Additionally, removing any infected leaves and applying a fungicide can help to manage the disease and prevent its spread.
Common Pests
Rhamnus uhligii is relatively resistant to most common pests. However, one potential pest to be aware of is the Spider Mite.4 These tiny arachnids feed on the leaves of the plant, causing stippling and discoloration. They are often attracted to hot, dry conditions, so regular watering and misting can help to prevent their infestation.5 If Spider Mites are present, washing the plant with a strong spray of water can help to dislodge them. Applying a horticultural oil or insecticidal soap can also help to control their population.
Another potential pest to watch out for is Scale.6 These insects appear as small, raised bumps on the stems or leaves of the plant and feed on its sap. Severe infestations can lead to leaf yellowing and drop as well as stem dieback. Inspecting plants regularly and removing any visible scales by hand can help to prevent their spread. Additionally, applying a horticultural oil or systemic insecticide can help to control the population.
Conclusion
Rhamnus uhligii is a relatively low maintenance plant that is resistant to most common pests and diseases. However, Powdery Mildew, Black Spot, Spider Mites, and Scale can all affect its growth and health under certain conditions. By implementing proper disease and pest management strategies, gardeners can help to protect the long-term health and vitality of this unique and beautiful shrub.
References:
1 Uhlig's Buckthorn (Rhamnus uhligii). (n.d.). Retrieved March 19, 2021, from https://www.gardeningknowhow.com/ornamental/shrubs/buckthorn/uhligs-buckthorn-shrubs.htm
2 Powdery Mildew. (2021, January 5). Retrieved March 19, 2021, from https://www.rhs.org.uk/advice/profile?PID=304
3 Black Spot. (2021, January 5). Retrieved March 19, 2021, from https://www.rhs.org.uk/advice/profile?PID=726
4 Spider Mites. (2021, January 5). Retrieved March 19, 2021, from https://www.rhs.org.uk/advice/profile?PID=429
5 Spider Mites: How to Get Rid of Them. (n.d.). Retrieved March 19, 2021, from https://www.today.com/series/how-often-should-you/how-get-rid-spider-mites-t179867
6 Scale Insects. (2021, January 5). Retrieved March 19, 2021, from https://www.rhs.org.uk/advice/profile?pid=229
