Overview
Tetraplasandra oahuensis (Gray) H.A.T. Harms, also known as ‘ohe‘ohe or ‘ohe k?pala‘ula, is a native plant found in the Hawaiian Islands. It is a member of the aralia family, Araliaceae, and is one of the largest trees in the lowland wet forest.
Appearance
The ‘ohe‘ohe tree can grow up to 50 feet tall and has a trunk diameter of up to 3 feet. The tree has a straight, cylindrical trunk, with smooth grayish-brown bark. The leaves are pinnately compound, with 5 to 9 leaflets, and can grow up to 18 inches long. The small flowers are produced in clusters, which later develop into small purple-black berries, each containing a single seed.
Uses
The ‘ohe‘ohe tree was used by the native Hawaiians for a variety of purposes. The flexible wood was used for fishing poles, spears and digging sticks, while the bark was used to make cordage and sandals. The leaves were used for medicine and the fruits were eaten fresh or used to make a fermented beverage. Today, the ‘ohe‘ohe tree is appreciated for its ornamental value and is sometimes used in landscaping projects.
Habitat and Distribution
The ‘ohe‘ohe tree is found in the wet lowland forests and stream valleys of the Hawaiian Islands, where it grows in rich, well-drained soils. It is commonly found on the islands of Oahu, Molokai, and Maui. The species is threatened by habitat loss due to deforestation, habitat degradation and introduced pests, and the International Union for Conservation of Nature has listed it as endangered.
Growth Conditions for Tetraplasandra oahuensis
Tetraplasandra oahuensis is a Hawaiian endemic tree species that prefers conditions typical of tropical rainforests. It can grow up to 15 meters tall and has a trunk diameter of up to 30 centimeters. Let's take a look at the specific growth conditions needed for this plant species.
Light Requirements
Tetraplasandra oahuensis prefers partial to full shade, making it an ideal choice for areas with limited direct sunlight, such as the understory of a forest. It can tolerate low light levels, but its growth will be slow compared to those exposed to higher light levels.
Temperature Requirements
The ideal temperature range for Tetraplasandra oahuensis is between 16°C and 27°C. It can survive in temperatures as low as 10°C or as high as 35°C, but its growth may be affected. In colder temperatures, it may slow down its growth, and in hotter temperatures, it may lose its leaves to prevent water loss through transpiration.
Soil Requirements
The soil should be well-draining, rich in organic matter, and slightly acidic. The ideal pH range is between 5.5 and 6.5. Tetraplasandra oahuensis is typically found in areas with volcanic soil, which is rich in nutrients and organic matter. It can tolerate periods of drought but prefers moist soil conditions.
Overall, Tetraplasandra oahuensis is a hardy plant species that can adapt to a wide range of conditions. However, to ensure optimal growth, it is best to provide it with partial to full shade, moderate temperatures, and well-draining, slightly acidic soil.
Cultivation Methods:
Tetraplasandra oahuensis, also known as `Oahu tree` or `ohe` is a tropical plant that belongs to the family of Araliaceae. It's a native plant from the Hawaiian Islands and it thrives in warm, humid climates. To cultivate this plant successfully, it requires well-draining soil that is rich in organic matter and kept slightly moist but not waterlogged. It thrives in partial shade to full sun, and it's best grown in USDA Hardiness zones of 9-11.
Watering Needs:
Proper watering is crucial for the growth and development of Tetraplasandra oahuensis. It requires regular watering to keep its soil slightly moist, but it shouldn't be over-watered to avoid fungal infections. During the hot season, it may require more frequent watering than the cold season. However, it's best to check its soil moisture level before watering.
Fertilization:
Regular fertilization is necessary for the healthy growth of Tetraplasandra oahuensis. Slow-release fertilizers, compost, or organic fertilizers can be applied once every four to six weeks during the growing season. Avoid over-fertilizing as this may lead to weak, leggy growth and may cause harm to the plant.
Pruning:
Pruning Tetraplasandra oahuensis is important to keep its growth in check and promote bushier growth. Pruning can be done in late winter or early spring before new growth emerges. Cut back the upper stem to encourage branching, and remove any dead or diseased stems from the plant. Also, remove any overcrowded, crossing, or rubbing branches to help the plant maintain its natural shape and form.
Propagation of Tetraplasandra oahuensis
Tetraplasandra oahuensis (Gray) H.A.T. Harms is a small tree or shrub that belongs to the family Araliaceae. It is native to Hawaii and is commonly known as O'ahu tree.
The propagation of Tetraplasandra oahuensis can be done by seed or vegetatively. This plant can produce a high number of seeds that can be collected and sown. However, since it takes a long time for Tetraplasandra oahuensis to flower and produce fruit, vegetative propagation is a more common method than seed propagation.
Vegetative propagation
Vegetative propagation of Tetraplasandra oahuensis can be done by stem cuttings and air layering. Both of these methods can produce plants that will be identical to the parent plant.
Stem cuttings: Stem cuttings can be taken from the parent plant during the growing season. Cuttings should be taken from non-flowering shoots and should be about 6 to 8 inches long. Remove leaves from the bottom half of the cutting and dip the cut end in rooting hormone. Plant the cutting in a well-draining soil mix and keep it moist. It should take about 6 to 8 weeks for the cutting to form roots, and another 6 to 8 weeks before it is ready for transplanting.
Air layering: Air layering is a method that is used for plants that are difficult to propagate by other methods. It involves removing a ring of bark from the stem of the parent plant, then covering the wound with sphagnum moss and wrapping it with plastic to create a mini greenhouse. Roots will develop where the bark has been removed. Once the roots have developed, the stem can be cut from the parent plant and potted.
Regardless of the method used, the newly propagated Tetraplasandra oahuensis should be kept in a warm, humid environment and watered regularly until it is established.
Disease and Pest Management for Tetraplasandra oahuensis
Tetraplasandra oahuensis (Gray) H.A.T. Harms, commonly known as Oahu tree, is a plant species native to Hawaii. Like all plants, it is susceptible to disease and pest infestations. Here are some of the common diseases and pests that might affect the plant and ways to manage them.
Common Diseases
1. Leaf spot: This fungal disease appears as small, dark spots on the leaves, which eventually turn yellow and fall off. To manage this disease, remove infected leaves and destroy them. Avoid overhead watering and make sure not to overcrowd the plants to improve air circulation.
2. Root rot: This disease is caused by several fungi that infect the roots, leading to wilted leaves and ultimately, death of the plant. To prevent root rot, ensure proper drainage and do not overwater the plant. If the disease has already affected the plant, remove it and destroy it to prevent further spread.
3. Powdery mildew: Powdery mildew is a fungal disease that appears as white powdery spots on the leaves, stems and flowers of the plant. To manage powdery mildew, prune the affected parts and dispose of them. Treat the remaining parts of the plant with a fungicide.
Common Pests
1. Black twig borer: This insect pest bores into the stems of the plant, causing wilted leaves and branch dieback. To manage this pest, prune and destroy affected branches. Treat the remaining parts of the plant with an insecticide.
2. Mealybugs: Mealybugs are small, white, cottony pests that suck the sap from the plant, causing stunted growth and yellowing leaves. To manage mealybugs, wipe them off using a cotton swab dipped in rubbing alcohol. Repeat the process every week until the infestation is under control.
3. Scale insects: Scale insects appear as small, oval, brown bumps on the stems and leaves of the plant. They suck the sap from the plant, causing yellowing leaves and stunted growth. To manage scale insects, scrape the bumps off with a toothbrush or a soft cloth dipped in soapy water. Repeat the process until the infestation is under control.
Regularly inspecting the plant for signs of disease and pest infestations can help identify problems early on and prevent their spread. Maintaining proper plant hygiene, providing adequate light, water, and fertilization, and avoiding stress can also help keep the plant healthy and resilient to common diseases and pests.
