Origin and Common Names
Strophanthus gratus (Wallich & Hook. ex Benth.) Baillon, commonly known as the Arrow-Poison Vine or Climbing Oleander, is a species of the genus Strophanthus which belongs to the family Apocynaceae. This plant is native to tropical and subtropical regions of Africa, including Somalia, Tanzania, Kenya, and Madagascar. It has been naturalized in Central and South America, as well as in India and Southeast Asia. This plant has a wide array of common names, such as Poison Rope, Lucky Bean Vine, and Thirty Pieces of Silver.Uses
Strophanthus gratus has been used traditionally for centuries as a source of medicine. The plant produces cardiac glycosides, which are compounds that have been used for treating heart ailments. This plant is also used for arrow poison in some African tribes, which is why it is commonly known as the Arrow-Poison Vine. The seeds of the plant contain toxiferine, an alkaloid that acts as a potent heart poison. As a result, this plant is highly poisonous and should only be used under the guidance of a medical professional.General Appearance
Strophanthus gratus is a woody vine that can grow up to 30 meters in length. It has smooth, slightly twisted stems that are green-grey in color. The leaves are alternate, oval-shaped, and have a waxy texture. The flowers of this plant are fragrant and trumpet-shaped, with five petals that are white or pale yellow. The fruit produced by the plant is a long, narrow, and pointed pod that contains numerous seeds. The seeds are brownish-black and have a flat shape with a tuft of silky hairs at one end. The plant is an important component of many traditional African medicines due to its cardiac glycosides, as well as being an interesting ornamental plant due to its beautiful white or pale yellow flowers.Light requirements
Strophanthus gratus typically requires full sunlight for healthy growth and flowering. It should be planted in an area where it can receive at least six hours of direct sunlight per day. Lack of sunlight can lead to stunted growth and poor flower production.
Temperature requirements
Strophanthus gratus is a tropical plant that can tolerate warm to hot temperatures. It should be grown in an area where the temperature ranges between 65 to 85 degrees Fahrenheit. It cannot tolerate frost or temperatures below 60 degrees Fahrenheit. If grown outside of its preferred temperature range, the plant may not thrive and could even die.
Soil requirements
The soil for Strophanthus gratus should be well-draining and fertile. It prefers slightly acidic to slightly alkaline soil with a pH range of 6.0 to 7.5. The plant requires adequate moisture, but the soil should not be waterlogged. A mix of sand, compost, and loam soil can be used to create the optimal growing medium for the plant.
Cultivation Methods
The Strophanthus gratus plant prefers well-drained soil and can grow well in both partial and full sunlight. The best time to plant this species is in the spring or early summer. Proper spacing between the plants should be maintained for good air circulation.
Watering Needs
To thrive, Strophanthus gratus requires moderate watering. During the growing season, it should be watered twice a week, but the frequency should be reduced during the winter months. Over-watering may result in root rot and plant death, so it is essential to avoid waterlogging the soil.
Fertilization
Proper fertilization is essential for the healthy growth of Strophanthus gratus. In the growing season (spring and summer), use a balanced fertilizer every two weeks. During the dormant season (fall and winter), reduce fertilization to once a month. It's also important to use a slow-release fertilizer that is rich in nitrogen, phosphorus, and potassium to promote growth and strong roots.
Pruning
Pruning is necessary for Strophanthus gratus to maintain an attractive shape and prevent pests and diseases. Young plants should be pruned sparingly during their first year to promote branching. As the plant matures, pruning should be done annually to remove old and dead stems. It's best to prune in the early spring before the new growth starts.
Propagation of Strophanthus gratus
Strophanthus gratus is a perennial climbing plant that belongs to the Apocynaceae family. The plant is native to tropical regions of Africa and India. The plant can be propagated through the following methods:
Seed Propagation
Seeds are a common method of propagation for Strophanthus gratus. The seeds should be collected from mature fruits and sown in well-drained soil. The seeds should be sown at a depth of about 1 cm and covered lightly with soil. Germination of the seeds occurs within 3-4 weeks.
Cuttings Propagation
Strophanthus gratus can also be propagated through stem cuttings. The cuttings should be taken from healthy plants during the growing season. The cuttings should be about 10-15 cm long and should have at least two nodes. The lower leaves should be removed, and the cuttings should be planted in a well-drained growing medium. The cuttings should be covered with plastic cover to maintain humidity levels. The cuttings will root within 4-6 weeks.
Air Layering Propagation
Air layering is a preferred propagation method for Strophanthus gratus. The stem of the plant is selected, and a ring of bark is removed from the stem. The cut area is then covered with moss and plastic wrap. Roots will form at the cut area within a few weeks. Once roots have formed, the stem can be cut off from the mother plant and planted in a well-drained soil mixture.
Disease and Pest Management for Strophanthus gratus (Wallich & Hook. ex Benth.) Baillon
Like other plants, Strophanthus gratus is prone to diseases and pests that can cause damage to the plant. However, with proper management, it is possible to control and prevent the occurrence of these problems. Here are some of the common diseases and pests that affect this plant and ways to manage them:
Common Diseases
1. Leaf Spot: This is a fungal disease that affects the leaves and causes small, round spots that are brown or black. It can cause premature defoliation and reduce the plant's vigor. To manage this disease, remove the infected leaves and destroy them. Also, avoid overhead watering to prevent the spread of spores.
2. Powdery Mildew: This is a fungal disease that forms a white powdery coating on the leaves, stems, and flowers. It can cause distortion of the leaves and reduce the plant's growth and vigor. To manage this disease, use fungicides that contain potassium bicarbonate or neem oil. Also, increase air circulation around the plant by pruning and training to prevent the development of the disease.
3. Root Rot: This is a fungal disease that affects the roots and causes them to rot, leading to poor growth and development of the plant. To manage this disease, avoid overwatering and ensure that the soil is well-drained and aerated. Also, use fungicides that contain copper oxychloride or mancozeb to prevent the spread of the disease.
Common Pests
1. Spider Mites: These are tiny pests that suck the sap from the leaves and cause yellowing and wilting. To manage these pests, spray the plant with neem oil or insecticidal soap, and increase humidity around the plant to prevent infestations.
2. Scale Insects: These are small pests that attach themselves to the leaves and stems and suck the sap from the plant, leading to distorted growth and development. To manage these pests, use a soft brush to remove them from the plant, or use insecticidal soap or neem oil to kill them.
3. Whiteflies: These are tiny pests that suck the sap from the leaves and can cause yellowing, wilting, and premature leaf drop. To manage these pests, use yellow sticky traps to catch them or spray the plant with insecticidal soap or neem oil.
Overall, maintaining good plant hygiene, avoiding over-fertilization, and keeping the plant healthy and well-watered can help prevent the occurrence of diseases and pests in Strophanthus gratus.
