Origin
Paramacrolobium coeruleum (Taub.) J.Léonard, also known as Blue Bean, is a plant species that belongs to the Fabaceae family. It is native to the tropical regions of Africa and is mainly found in the countries of Angola, Tanzania, Zambia, and Zimbabwe.
Common Names
Blue Bean is the most common name used to refer to Paramacrolobium coeruleum. It is also known as Azulão in Portuguese, Mzungutu in Swahili, and Musumpa in the Chichewa language.
Uses
Paramacrolobium coeruleum has several uses in traditional African medicine. The plant has antifungal properties and is used to treat fungal infections such as ringworm. The roots, bark, and leaves of the plant are used to make a decoction that is believed to have antipyretic, anti-inflammatory, and analgesic effects.
The plant is also used for timber and fuelwood due to its large stem and its ability to withstand high temperatures. In addition, the seeds of Paramacrolobium coeruleum are edible and can be cooked or roasted as a source of food.
General Appearance
Paramacrolobium coeruleum is a perennial plant that grows up to 20 meters tall. It has a straight stem and a large canopy of dark green pinnate leaves that are about 60 cm long. The flowers are bright blue and are arranged in clusters of up to 30 per stem. Each flower has a tubular shape with five petals. The fruit is a flat pod that is about 10 cm long and contains a single seed.
Light Conditions
Paramacrolobium coeruleum (Taub.) J.Léonard typically prefers bright indirect light. It can also adapt to partial shade but may not bloom as much as it would in bright light. Direct sunlight should be avoided as it can cause leaf burn.
Temperature
The ideal temperature for Paramacrolobium coeruleum (Taub.) J.Léonard falls between 18 to 24°C. This plant can tolerate cooler temperatures but not frost. During the winter season, the room temperature should not fall below 15°C as it can harm the plant growth.
Soil Requirements
Paramacrolobium coeruleum (Taub.) J.Léonard prefers well-drained soil. The soil should be able to hold the moisture to avoid excess dryness, but it should not be waterlogged at any point. A recommended soil mix for this plant involves equal parts of peat moss, perlite, and vermiculite. This plant can tolerate slightly acidic to neutral soil with a pH range between 5.5 to 7.5.
Cultivation Methods
Paramacrolobium coeruleum, commonly known as Taub, is a tropical tree that requires warm temperatures to grow and thrive. It can be propagated by seeds, which should be soaked in water for a few hours before planting in a well-draining pot or soil.
The plant prefers indirect sunlight and can be grown both indoors and outdoors. It can also withstand some shade and requires a warm climate to grow well.
It is important to provide support for the tree as it grows taller, to prevent it from toppling over. Staking is recommended during the early years of growth to ensure the proper development of the trunk and branches.
Watering Needs
Paramacrolobium coeruleum requires regular watering to keep the soil moist. Water the plant deeply once a week, allowing the water to penetrate the roots. This will help the plant to develop a strong root system and promote healthy growth.
It is important to avoid overwatering the plant as it can lead to root rot and damage the plant. Check the soil's moisture level before watering the tree to avoid excess watering.
In addition, it is recommended to reduce watering during the dormant season to prevent waterlogging and root rot.
Fertilization
Fertilization is important for the growth and development of Paramacrolobium coeruleum. Apply a balanced fertilizer once a month during the growing season from spring through fall.
A slow-release fertilizer can also be added to the soil to provide nutrients for the plant over an extended period of time.
It is recommended to stop fertilizing the plant during the dormant season to allow it to rest and conserve energy for the next growing season.
Pruning
Pruning is important to shape Paramacrolobium coeruleum and remove dead or damaged branches. It should be done during the dormant season when the plant is not actively growing.
It is important to use sharp and clean pruning tools to avoid damaging the tree. Remove a maximum of one-third of the total branches and foliage, and avoid pruning back to the trunk of the tree.
Regular pruning will promote healthy branching, improve the overall appearance of the tree, and help to prevent disease and insect problems.
Propagation of Paramacrolobium coeruleum
Paramacrolobium coeruleum is a leguminous shrub that can be propagated through several methods, including seed propagation, stem cuttings, and air layering.
Seed Propagation
Seeds should be collected from mature pods after they have dried and turned light brown. The seeds must be scarified (the process of breaking the tough seed coat) by either filing or soaking in hot water for 24 hours before planting. Seeds can be directly sown in the ground or started in seed trays filled with well-draining soil. It is advisable to plant several seeds to ensure germination and thinning out can be done later. Seedlings should be protected from direct sunlight and watered daily until they are ready to be transplanted.
Stem Cuttings
Paramacrolobium coeruleum can also be propagated through stem cuttings. Cuttings should be taken from healthy and mature plants during the rainy season when the plant is actively growing. Cuttings should be from semi-hardwood with no flowers or buds. Cuttings should be about 15cm–20cm long and planted in a well-draining, moist soil mixture of sand and peat. Cuttings require a high level of humidity, and plastic covers or misting of the soil can ensure this is achieved. Rooting should occur within 4–6 weeks, after which the covering can be removed.
Air Layering
Air layering is a process of inducing rooting in a stem while it is still attached to the parent plant. This method is suitable for plants with woody stems, including Paramacrolobium coeruleum. A section of the stem is wounded by removing a strip of bark and applying rooting hormone. The wounded area is then covered with moist sphagnum moss or coconut coir and wrapped with plastic wrap to retain moisture. Roots should start to form within 8–10 weeks after which the stem can be cut, and the new plant can be transplanted.
Disease and Pest Management for Paramacrolobium coeruleum (Taub.) J.Léonard
Paramacrolobium coeruleum (Taub.) J.Léonard, also known as African Indigo, is a plant native to Africa that is grown for ornamental and medicinal purposes. However, like any other plants, it is susceptible to diseases and pests that can affect its growth and even kill it. Here are some common diseases and pests that may affect Paramacrolobium coeruleum, and ways to manage them:
Diseases
One of the most common diseases that affect Paramacrolobium coeruleum is leaf spot. This is caused by a fungus that forms small, circular brown spots on the leaves of the plant. The spots may combine and spread, causing the leaves to wither and die. To manage this disease, it is essential to avoid wetting the leaves while watering the plant and to remove any infected leaves immediately. Additionally, applying a fungicide can help prevent the spread of the disease.
Anthracnose is another fungus that can cause similar symptoms to leaf spot. It forms dark brown spots on the leaves, and may cause defoliation, which will weaken the plant. To manage anthracnose, remove the infected leaves, and apply a fungicide.
Pests
Mealybugs are common pests that may infest Paramacrolobium coeruleum. They suck plant sap and reproduce quickly, which can cause severe damage to the plant. To manage mealybugs, use a cotton swab dipped in rubbing alcohol to remove them from the plant, or apply an insecticidal soap spray that will suffocate and kill them.
Spider mites are also a common pest that feed on plant sap, reproduce quickly, and produce webs that can cover leaves and stems. To manage spider mites, wash the plant regularly with a strong stream of water to dislodge the mites from the plant. Alternatively, applying an insecticidal soap or neem oil can help reduce their population.
Scale insects are another common pest that feed on plant sap, reproduce quickly, and produce a sticky substance that attracts ants. To manage scale insects, use a cotton swab dipped in rubbing alcohol or horticultural oil to remove them from the plant. Applying insecticidal soap or neem oil can also help reduce their population.
In summary, it is important to regularly inspect Paramacrolobium coeruleum for signs of disease and pests to prevent them from spreading and damaging the plant. Providing proper care and cultural practices, such as regular watering, fertilization, and pruning, can also help keep the plant healthy and resistant to diseases and pests.
