Introduction
Celtis usambarensis Engl. is a plant species that belongs to the Cannabaceae family. It is commonly known as Usambara nettle or African hackberry.
Origin
The plant species is native to East Africa, specifically in Kenya, Tanzania, and Mozambique. It is a typical component of the native forest vegetation and often occurs at altitudes of 1400-2000m above sea level.
Appearance
The Celtis usambarensis is a tall tree that can grow up to 25m high. Its bark is smooth and grey while its leaves are toothed and serrated, with a rough texture and a light green color. Its fruit is a small edible drupe that is green when unripe and turns orange when mature.
Uses
Various communities in East Africa use Celtis usambarensis for its medicinal properties. The roots, bark, and leaves of the tree are used to prepare concoctions to treat various ailments such as diarrhea, bilharzia, and pneumonia. The fruit also provides a rich source of food for birds and other animals. Other commercial uses include its use in making furniture, baskets, and other handicraft items.
Light Requirements
Celtis usambarensis Engl. thrives in moderate to full sunlight. It can tolerate semi-shaded conditions, but it may not grow as robustly as it would in a sunnier location. In its native habitats, the plant grows under the protection of taller trees, which offer filtered sunlight.
Temperature Preferences
This plant prefers warm temperatures between 20°C to 30°C (68°F to 86°F). It is not frost-tolerant and requires temperatures above 0°C (32°F) to survive. Celtis usambarensis generally thrives in tropical and subtropical climates.
Soil Needs
Celtis usambarensis can grow in a variety of soils, including clay, loam, sand, and even rocky soils. However, it prefers well-draining and moist soil. The plant can also tolerate slightly acidic to slightly alkaline soil conditions. It can be grown in areas with an average rainfall of between 700 and 1000 mm.
Cultivation methods for Celtis usambarensis Engl.
Celtis usambarensis Engl., commonly known as the African hackberry, is a fast-growing, deciduous tree that can reach up to 30 meters in height. It is best grown in well-drained soils and requires full sun to partial shade. It can be propagated through seeds or through stem cuttings.
It is essential to provide adequate space for the tree to grow, and it is best planted in an area sheltered from strong winds.
Watering needs for Celtis usambarensis Engl.
Celtis usambarensis is a drought-tolerant tree, but it requires regular watering during its first few months after planting to ensure proper establishment. Once established, the tree can thrive with infrequent, deep watering.
It is essential to monitor soil moisture levels to ensure that the tree is not over-watered, as this can lead to root rot.
Fertilization for Celtis usambarensis Engl.
Celtis usambarensis does not require frequent fertilization, but it can benefit from occasional applications of organic fertilizer to promote healthy growth. Fertilizers that are high in nitrogen should be avoided as they can promote excessive, weak growth that is susceptible to diseases and pests.
Pruning for Celtis usambarensis Engl.
Celtis usambarensis requires minimal pruning, but it can benefit from the removal of damaged or dead branches. Pruning should be done during the tree's dormant season to minimize stress. It is essential to use proper pruning techniques to avoid damaging the tree and to ensure that it has a natural appearance.
Overall, Celtis usambarensis is a low-maintenance tree that can thrive in a wide range of growing conditions with minimal care.
Propagation of Celtis usambarensis Engl.
Celtis usambarensis Engl., also known as African hackberry, can be propagated through different methods, including seeds and cuttings.
Propagation through seeds
The ideal time for collecting seeds of Celtis usambarensis is during autumn, when the fruits are mature. The seeds should be extracted from the fleshy fruit, washed, and dried in shade before use.
After preparing the seeds, sow them in a well-draining soil mix. Cover the seeds with a thin layer of soil and keep them moist. The ideal temperature for germination is between 20-25 °C.
Seeds of Celtis usambarensis can take up to six months to germinate, so patience is necessary. Once germination occurs, the seedlings should be transplanted into individual containers or planted directly into the ground.
Propagation through cuttings
Celtis usambarensis can also be propagated through stem cuttings. The cuttings should be taken during the spring when the new growth appears.
The cuttings should be around 15-20 cm long and should include a few leaves. Remove the leaves from the bottom half of the cutting and dip the cut end in rooting hormone powder.
Insert the cutting into a well-draining soil mix and keep it moist. The cutting should be placed in a shaded area to avoid direct sunlight, which could damage the young plant. In about six to eight weeks, the cutting will develop roots and can be transplanted into individual containers or planted in the ground.
Propagation through cuttings is an excellent method to produce clones of Celtis usambarensis with the same characteristics as the parent plant.
Disease and Pest Management for Celtis usambarensis Engl.
Celtis usambarensis Engl. is a tree species known for its beautiful leaves and ability to tolerate drought. However, like all plants, it is also vulnerable to diseases and pests. Here are some common diseases and pests that might affect Celtis usambarensis Engl., and suggestions on how to manage them.
Diseases
Anthracnose: This disease is caused by a fungal pathogen that attacks the leaves, branches, and fruits of the plant. Symptoms include brown or black spots on the leaves and wilted or deformed leaves. To manage anthracnose, prune infected branches, remove infected leaves, and ensure good air circulation around the plant.
Root Rot: This disease is caused by a soil-borne fungus that attacks the roots of the plant. Symptoms include yellowing or wilting leaves, stunted growth, and root decay. To manage root rot, remove infected plants and improve soil drainage. Avoid overwatering and make sure the plant is not sitting in standing water.
Pests
Scale Insects: These pests are small, hard, and waxy and are usually found on the undersides of the leaves. Symptoms include yellowing and wilting leaves, and a sticky substance called honeydew that attracts ants. To manage scale insects, remove affected leaves and use insecticidal soap or horticultural oil.
Aphids: These pests are small, soft-bodied insects that feed on the sap of the plant. Symptoms include distorted leaves and stunted growth. To manage aphids, use insecticidal soap or horticultural oil, or release natural predators such as ladybugs or lacewings.
Caterpillars: These pests are the larvae of moths or butterflies and feed on the leaves of the plant. Symptoms include chewed or skeletonized leaves. To manage caterpillars, handpick the larvae and destroy them or use an insecticide specifically labeled for caterpillar control.
By keeping a watchful eye and taking the appropriate action, you can help maintain the health and beauty of your Celtis usambarensis Engl. plant.
