Origin
Erythrina sandwicensis O. Deg., commonly known as Wiliwili, is a small to medium-sized tree that is native to Hawaii. It is found in dry forests and lowlands, and is one of only six native species of Erythrina in Hawaii.
Common Names
The common name of Erythrina sandwicensis is Wiliwili, which means "repeated twisting" in Hawaiian, referring to the twisted shape of the seed pods. It is also known as Indian coral tree or Hawaiian coral tree, due to its bright red flowers resembling coral.
Uses
The Wiliwili tree has many traditional uses in Hawaiian culture. Its wood was used to make canoes, surfboards, and furniture, and the flowers were used to make leis. The Wiliwili tree also has environmental uses, as it has a deep taproot that helps to stabilize soil and prevent erosion.
General Appearance
Erythrina sandwicensis is a deciduous tree that can grow up to 40 feet tall. It has a short, stout trunk and spreading branches that form a broad, rounded canopy. The leaves are large and compound, with three leaflets that are each up to six inches long. The flowers are bright red or orange, and grow in clusters on long stalks that arise from the branches. The fruit is a long, twisted pod that contains several seeds.
Light Requirements
Erythrina sandwicensis O. Deg., commonly known as Hawaiian coral tree, requires full sun exposure or partial shade to grow. It thrives in bright and direct sunlight, but it can also tolerate some shade. When planted in partial shade, it tends to grow slower and produce fewer flowers.
Temperature Requirements
This plant prefers warm to hot temperatures and can grow well in areas with temperatures ranging from 60 to 90 degrees Fahrenheit. It is sensitive to frost and cannot tolerate freezing temperatures, so it is not suitable for growing in areas with prolonged cold winters.
Soil Requirements
Erythrina sandwicensis O. Deg. typically grows well in well-draining and slightly acidic soil with a pH ranging from 5.5 to 6.5. It prefers soil that is rich in organic matter and has good moisture retention. However, it can tolerate a range of soil types, including sandy, loamy, and clay soils. The plant is also capable of growing in poor soil conditions, but it may not produce as much foliage or flowers.
Cultivation
Erythrina sandwicensis O. Deg. is a shrub or small tree that thrives in well-drained and rich soils. It grows best in tropical and subtropical climates where there is adequate sunlight.
If you plan to cultivate Erythrina sandwicensis, make sure to select an ideal location with abundant sunlight and with proper drainage.
The plant requires regular watering until it fully establishes, and then it will need less frequent watering. Ensure to mulch around the base to help conserve moisture.
Erythrina sandwicensis is best propagated through seeds or stem cuttings. Stem cuttings should be taken from mature wood during the summer.
Watering Needs
Erythrina sandwicensis O. Deg. plant requires regular watering until it fully establishes, then less frequent watering is needed. However, ensure the soil does not dry out as the plant prefers slightly moist soil.
The plant is prone to root rot, so avoid over-watering and ensure adequate drainage in the planting site to prevent waterlogging.
Fertilization
Erythrina sandwicensis does not require excessive fertilization, and it is recommended to use a balanced fertilizer to supply the necessary nutrients.
You can add a general-purpose fertilizer containing essential nutrients such as nitrogen, phosphorus, and potassium during the growing season to enhance vegetative growth.
After application, water the plant to help distribute the fertilizer evenly and prevent damage to the roots.
Pruning
Pruning is vital for maintaining the shape and size of Erythrina sandwicensis. It should be carried out after flowering in late winter or early spring.
Remove any dead, diseased, or damaged branches and cut back any overgrown shoots to promote bushy growth.
When pruning, ensure to use clean, sharp tools to prevent disease spread, and regularly sterilize your pruning tools in boiling water to kill disease-causing pathogens.
Propagation of Erythrina sandwicensis O. Deg.
Erythrina sandwicensis O. Deg. can be propagated through several methods: seeds, cuttings, and grafting. Each method has its own advantages and disadvantages, and choosing the appropriate method depends on the resources available, the desired outcome, and the level of expertise of the propagator.
Seed Propagation
Seed propagation is the most common method for Erythrina sandwicensis O. Deg. and is relatively easy. The seeds can be harvested from mature pods and should be soaked in water for 24 hours before planting in a well-draining potting mix. The seeds should be planted no deeper than three times their diameter and kept moist. Germination can take up to two months and can be encouraged by warm temperatures and high humidity. Once the seedlings have developed their first pair of true leaves, they can be transplanted into a larger container or directly into the ground.
Cutting Propagation
Cutting propagation is a relatively easy method that involves taking cuttings from mature plants and rooting them in a well-draining potting mix. The best time to take cuttings is in the early spring, before the plant has begun to put out new growth. The cuttings should be about six inches long and have at least two nodes. The bottom leaves should be removed, and the cutting should be dipped in rooting hormone before planting in moist potting soil. Keep the soil moist and provide bright, indirect light. Roots should develop in 6-8 weeks, and once established, the new plants can be transplanted into larger containers or directly into the ground.
Grafting
Grafting is a more advanced propagation method that involves joining a scion, or cutting from the desired plant, onto a rootstock from a related plant. The rootstock provides the plant's root system, while the scion provides the desired characteristics, such as flower color or plant size. Grafting is typically done in the early spring when the plants are dormant. The scion should be taken from a healthy, disease-free plant and should be cut at an angle to increase the surface area for the graft. The rootstock should be cut to fit the scion, and the two should be wrapped tightly with grafting tape. The grafted plant should be kept in a high humidity environment until the graft has taken root, which can take several months.
Disease Management
There are several common diseases that can affect Erythrina sandwicensis O. Deg. One of the most significant ones is root rot, caused by fungal pathogens such as Phytophthora spp. and Fusarium spp. Symptoms of root rot include wilting, yellowing of the leaves, and stunted growth. To manage root rot in Erythrina sandwicensis, it is essential to plant the trees in well-draining soil that is not waterlogged. Avoiding over-watering and properly spacing the trees can also help prevent root rot. In severe cases, fungicides can be applied to the soil, but this should be done in consultation with an expert to prevent damage to the other beneficial organisms in the soil.
Another common disease that can affect Erythrina sandwicensis is anthracnose, a fungal disease that causes small, dark, sunken lesions on the leaves, stems, and flowers. Severe infestations can cause defoliation and twig dieback. To manage anthracnose, infected plant material should be promptly removed and destroyed. Fungicides containing active ingredients such as azoxystrobin and chlorothalonil can be used to prevent the spread of the disease.
Pest Management
Erythrina sandwicensis O. Deg. is also vulnerable to pest attacks, including aphids, mealybugs, and spider mites. These pests typically cause yellowing of the leaves, stunted growth, and wilting by sucking sap from the trees. To manage these pests, regular monitoring is recommended, and infested plant material should be promptly removed and destroyed. Natural enemies such as ladybugs and lacewings can help control aphids and spider mites.
In severe infestations, insecticides can be used, but this should be done in consultation with an expert to prevent damage to beneficial insects and other organisms. Neem oil, insecticidal soap, and insecticidal sprays containing pyrethrin can be effective against these pests. It is essential to follow the label directions for proper use, dosage, and application timing.
