Plant Description:
Tarenna graveolens (S.Moore) Bremek. subsp. arabica (Cufod.) Bridson is a small to medium-sized shrub that belongs to the family Rubiaceae. It grows up to 2 meters tall and 2.5 meters wide. The plant has dark green, glossy leaves with a leathery texture and a pointed end. The leaves are arranged in an opposite manner on the stem, and the veins are easily visible.
Origin:
Tarenna graveolens (S.Moore) Bremek. subsp. arabica (Cufod.) Bridson is native to the Arabian Peninsula, including Yemen, Oman, and Saudi Arabia. It grows in the rocky areas of mountains and valleys at an altitude of up to 2000 meters above sea level.
Common Names:
Tarenna graveolens (S.Moore) Bremek. subsp. arabica (Cufod.) Bridson is commonly known as 'Qarad' or 'Qarahd' in Arabic, which refers to its bitter taste.
Uses:
Tarenna graveolens (S.Moore) Bremek. subsp. arabica (Cufod.) Bridson has many traditional medicinal uses. Its leaves and bark are used to treat various ailments, including fever, diarrhea, joint pains, and insect bites. The plant has also been used as a natural insect repellent. Additionally, the plant's wood is used for fuel and charcoal production.
Light Requirements
The plant Tarenna graveolens (S.Moore) Bremek. subsp. arabica (Cufod.) Bridson requires a bright, indirect light source to grow optimally. Direct sunlight should be avoided as it can damage the foliage and stunt growth. Ideally, the plant should be placed near a window that receives morning or evening sun.
Temperature
The ideal temperature range for Tarenna graveolens (S.Moore) Bremek. subsp. arabica (Cufod.) Bridson is between 18-25°C (64-77°F). Extreme temperatures should be avoided as they can cause stress and damage to the plant. Nighttime temperatures should not fall below 15°C (59°F) as this can cause the plant to drop its leaves.
Soil Requirements
The plant prefers well-draining soil that is rich in organic matter. A mix of peat moss and perlite or coarse sand is ideal. The soil pH should be slightly acidic, around 5.5 - 6.5. The plant does well in soil that is kept consistently moist but not waterlogged. Overwatering can cause root rot and other fungal diseases.
Cultivation
When cultivating Tarenna graveolens (S.Moore) Bremek. subsp. arabica (Cufod.) Bridson, it is essential to provide it with a warm and damp habitat. The plant is relatively easy to grow in warm climates, preferring full sunlight or partial shade.
Watering Needs
Tarenna graveolens (S.Moore) Bremek. subsp. arabica (Cufod.) Bridson requires frequent watering to ensure that the soil remains moist, but it can also tolerate short periods of drought. One should drain off excess water to avoid waterlogging, which may lead to root rot.
Fertilization
Fertilization of Tarenna graveolens (S.Moore) Bremek. subsp. arabica (Cufod.) Bridson should be done regularly with organic fertilizers, as they provide necessary nutrients and stimulate growth. The plant will benefit most from fertilization during the growing season, spring through summer.
Pruning
It is recommended that pruning be done regularly to keep the plant healthy and maintain its shape. Careful attention is needed to prevent overtrimming, which can cause long-term damage to the plant.
Propagation of Tarenna graveolens subsp. arabica
Tarenna graveolens subsp. arabica can be propagated by several methods:
Seed propagation
Seeds of Tarenna graveolens subsp. arabica can be collected from the mature fruits. The seeds need to be cleaned and dried before sowing. They can be sown in a well-draining soil mix and kept moist until germination. The best time for sowing is during the rainy season.
Cuttings propagation
Tarenna graveolens subsp. arabica can also be propagated by stem cuttings. The cuttings should be taken from mature and healthy plants. The stem cuttings should be around 15 cm in length and have several leaves on them. The cuttings should be dipped in a rooting hormone and planted in a well-draining soil mix. They should be placed in a shaded area and kept moist until they develop roots.
Air layering propagation
Air layering is another method to propagate Tarenna graveolens subsp. arabica. This method involves making a small cut on a mature stem and wrapping it with moist sphagnum moss and plastic wrap. Roots will develop where the cut was made. Once well developed, the rooted layer can be separated from the parent plant and planted in a well-draining soil mix.
Disease Management
Tarenna graveolens subsp. arabica is susceptible to several diseases that can cause severe damage. The most common diseases affecting this plant are:
- Leaf spot disease: This is caused by fungal pathogens that manifest as small, circular spots on the leaves. To manage this, infected leaves should be removed and destroyed immediately. Fungicides can also be used, but they should be applied in compliance with the manufacturer's instructions.
- Root rot: This disease is caused by fungal pathogens that thrive in waterlogged soil. To prevent this, it is important to ensure adequate drainage. If the plant is already infected, it should be treated with a fungicide that is effective in managing root rot.
- Bacterial blight: This disease is caused by the Xanthomonas pathogen and manifests as brown, water-soaked spots on the leaves. Infected parts of the plant should be removed, and copper-based fungicides can be used to manage the disease.
Pest Management
Tarenna graveolens subsp. arabica is also prone to attack by pests, which can be detrimental if left unchecked. The most common pests that can attack this plant include:
- Aphids: These are small, pear-shaped insects that suck plant sap, causing the leaves to curl and turn yellow. To manage them, a steady stream of water can be used to dislodge them from the plant. Insecticides can also be used, but they must be used in compliance with the manufacturer's instructions.
- Spider mites: These are tiny, eight-legged pests that can cause severe damage to the plant by feeding on the leaves. They usually manifest as tiny, yellow spots on the leaves. A steady stream of water can also be used to dislodge them from the plant, and insecticidal soap can be used to control their spread.
- Scale insects: These pests usually appear as tiny, hard bumps on the leaves, and they suck plant sap, causing the leaves to turn yellow and drop. To manage them, a brush or cotton swab dipped in alcohol can be used to remove them from the plant. Insecticides can also be used, but must be used in compliance with the manufacturer's instructions.
