Overview of Exostema caribaeum (Jacq.) J.A. Schultes
Exostema caribaeum, also known as the princess flower, is a small tree or shrub that belongs to the family Rubiaceae. It is indigenous to the Caribbean region and is commonly found growing near the coastlines in sandy soils. The plant is known for its showy, fragrant flowers that are used for medicinal purposes and ornamental purposes in landscaping.
General Appearance
The princess flower can grow up to 15-20 feet in height and has a relatively slow growth rate. The bark of the plant is dark brown and as the plant matures, the bark becomes fissured and scaly. The leaves are ovate, with a glossy appearance, and can grow up to 7 inches long. The plant produces fragrant flowers that are about 2-3 inches in diameter and have a vibrant purple or violet color. The flowers bloom from late spring to fall and have a sweet, pleasant fragrance that is attractive to hummingbirds and butterflies. The plant produces small, round, and green fruit that contains a single seed.
Common Names
Exostema caribaeum is commonly known as the princess flower, as mentioned earlier, along with numerous other names such as Lignum-vitae, Caribbean pine, and bully tree.
Uses
The bark of the princess flower has been traditionally used in folk medicine by various Caribbean cultures to treat conditions such as fever, diarrhea, and hypertension. Scientific studies have shown that the bark contains alkaloids that have antifungal, antitumor, and anti-inflammatory properties. Additionally, the plant is used in ornamental landscaping due to its stunning flowers and glossy leaves.
In conclusion, Exostema caribaeum is a beautiful and versatile plant that boasts an array of medicinal and ornamental uses.
hereLight Requirements
Exostema caribaeum prefers partial to full shade as direct sunlight can cause leaf scorching. It thrives in shade-tolerant conditions and can even grow under the shade of taller trees.
Temperature Requirements
The plant prefers warm, tropical temperatures ranging from 20°C to 30°C (68°F to 86°F). It is not frost tolerant, and temperatures below 10°C (50°F) can damage or kill the plant.
Soil Requirements
Exostema caribaeum prefers well-draining, moist soil rich in organic matter. It can grow in a wide range of soil types, including sandy, loamy, and clay soils. The ideal pH range is between 5.5 to 6.5, slightly acidic to mildly acidic.
Cultivation of Exostema Caribaeum
Exostema caribaeum, commonly known as "boxwood bark," is a tropical plant that grows well in warm, humid climates. To cultivate this plant, you will need to provide it with the right growing conditions.
The plant prefers well-draining soil with a slightly acidic pH. It thrives in partial shade or filtered sunlight. Direct sunlight can cause leaf scorching, so it's best to provide some shade during the hottest part of the day.
Watering Needs
Exostema caribaeum prefers consistently moist soil. It's important to avoid overwatering, as this can lead to root rot. Check the soil regularly and water when the top inch feels dry to the touch. During hot and dry periods, the plant may require more frequent watering.
Fertilization
For optimal growth and flowering, Exostema caribaeum requires regular fertilization. Use a balanced fertilizer with equal parts nitrogen, phosphorus, and potassium. Apply the fertilizer every two to three months during the growing season, following the instructions on the package.
Pruning
To maintain the compact shape of Exostema caribaeum, prune the plant regularly. Spring and fall are the best times for pruning. Remove any dead or diseased branches to prevent the spread of disease. You can also trim back the tips of the branches to encourage bushier growth and more flowers.
With proper care, Exostema caribaeum can be a beautiful addition to any tropical garden. Be sure to provide it with the right growing conditions, water it regularly, fertilize it consistently, and prune it regularly to keep it healthy and thriving.
Propagation of Exostema caribaeum
Exostema caribaeum (Jacq.) J.A. Schultes is a beautiful shrub found in the Caribbean Islands, Central America, and northern parts of South America. It is often grown as an ornamental plant due to its attractive foliage and showy flowers. Propagation of Exostema caribaeum is specifically through cuttings and seeds.
Propagation by Cuttings
Propagation through cuttings is a convenient method for producing multiple plants that are genetically identical to the parent plant. The best time to take cuttings is in the spring or early summer before the plant starts producing flowers. The cutting should be about 4-6 inches long and should come from the current season's growth.
Remove the leaves from the bottom half of the cutting and dip the cut end into rooting hormone. Insert the cuttings into a pot filled with moistened potting mix and cover it with a plastic bag to create a humid environment. Place the pot in a bright but indirect light location and keep the soil evenly moist. After a few weeks, the cutting will start to develop roots, and you can remove the plastic bag.
Propagation by Seeds
Propagation of Exostema caribaeum can also be done through seeds. Collect seeds from mature fruits and sow immediately in pots containing a good quality, well-draining potting mix. Sow seeds no deeper than a quarter of an inch and water them gently. Cover the pot with plastic to create a humid environment and place it in a bright location, avoiding direct sunlight.
Keep the soil evenly moist, and the seeds will start to germinate within a few weeks. Once the seedlings have their first true leaves, remove the plastic cover, and move the pot to a bright, sunny location. Continue to water the seedlings regularly, and transplant them into individual pots when they outgrow their initial containers.
Propagation of Exostema caribaeum through either cuttings or seeds can be very successful if the proper techniques are followed.
Disease Management
The Exostema caribaeum (Jacq.) J.A. Schultes is generally resistant to most diseases. However, it may suffer from fungal infections like leaf spot, stem rot, and powdery mildew.
Leaf spot is caused by the fungus Cercospora exostematis. The infected leaves develop yellow or brown spots, which gradually increase in size and merge to form large, dead areas. To manage this infection, it is recommended to remove and destroy the infected leaves and treat the plant with a fungicide such as copper-based sprays. Maintaining proper air circulation around the plant will also help reduce the spread of the disease.
Stem rot is caused by the fungus Pythium ultimum, which infects the stem causing it to rot and eventually kill the plant. This issue can be managed by avoiding overwatering, providing proper soil drainage and by using a fungicide recommended for the infection.
Powdery mildew is caused by the fungal pathogen Oidium sp and is a common disease that affects many plant species. The signs of this condition include a white, powdery coating on leaves, flowers, and stems. To manage this disease, it is recommended to remove the infected leaves, avoid overcrowding, maintain proper air circulation, and use a recommended fungicide.
Pest Management
The Exostema caribaeum (Jacq.) J.A. Schultes may suffer from pests such as aphids, mealybugs, and spider mites.
Aphids are small insects that suck sap out of the plant leaving them weak and vulnerable. These pest can be seen on the undersides of the leaves. In case of an infestation, they can be controlled by spraying the plant with water and using insecticidal soap as well as maintaining a healthy environment that promotes beneficial insects and discourages aphids.
Mealybugs are small, white, and very mobile insects that can cause stunted growth and wilting of the plant. The infestation can be identified by the white cotton-like material found on the plant. To manage this infestation, it is important to remove the infected parts and use neem oil-based insecticides which are effective against mealybugs.
Spider mites can cause the leaves of Exostema caribaeum (Jacq.) J.A. Schultes to wilt, turn yellow, and fall off. The infestation is identified by the presence of small webs under the leaves, which are produced by the mites. To manage spider mites, it is recommended to use a miticide for the pest and prune away heavily infected leaves.
Monitoring the plant regularly will help identify any disease or pest issues early on, allowing for quicker and more effective management measures to be implemented.
