Overview of Diospyros sandwicensis (A. DC.) Fosberg var. rotundata St. John
Diospyros sandwicensis (A. DC.) Fosberg var. rotundata St. John, also known as the round-leafed ebony, is a flowering plant species in the genus Diospyros. This plant is endemic to Hawaii, specifically to the islands of Kauai, Oahu, Molokai, Lanai, Maui, and Hawaii Island. The species is threatened due to habitat destruction, competition, and browsing by introduced mammals.
General Appearance
The Diospyros sandwicensis (A. DC.) Fosberg var. rotundata St. John is a small tree that grows up to 10 meters tall. The bark is grayish-brown and rough to the touch. The leaves are round, glossy, and dark green, measuring up to 10 centimeters in length and width. The flowers are small, white, and bell-shaped, measuring up to 2 centimeters in diameter. The fruit of the tree is edible and measures up to 2 centimeters in diameter. The fruit is green when unripe and turns yellow or orange when ripe.
Common Names
The Diospyros sandwicensis (A. DC.) Fosberg var. rotundata St. John is commonly known as the round-leafed ebony, Hawaiian ebony, or haole koko in Hawaiian.
Uses
The fruit of the Diospyros sandwicensis (A. DC.) Fosberg var. rotundata St. John is used in traditional Hawaiian medicine for its medicinal properties. The fruit is believed to have antibacterial and anti-inflammatory properties and is used for treating infections and abscesses. The hard wood of the tree is also used for carving and making musical instruments. However, due to the species being endangered, it is not recommended to harvest or use the tree or its parts without proper permission and regulations.
Light Requirements
Diospyros sandwicensis var. rotundata can be categorized as a shade-tolerant species that can grow in various light conditions. However, it thrives best under partial shade, receiving around 30-50% of full sunlight. Full-sun exposure may be detrimental to the plant's growth and survival, causing leaf scorch and wilting.
Temperature Requirements
Diospyros sandwicensis var. rotundata is native to the Hawaiian Islands, where the climate is warm and humid. The plant prefers warm temperatures ranging between 20-30°C (68-86°F) and high humidity levels (around 70-80%). It can tolerate some temperature fluctuations but may suffer under extremely hot or cold climates.
Soil Requirements
The plant thrives in well-drained soils that are rich in nutrients. A soil pH ranging from 5.5 to 7.5 is optimal. The roots of Diospyros sandwicensis var. rotundata prefer slightly acidic soils, specifically those with high organic matter content, as they retain moisture well. The plant can tolerate various soil types, including clay, loam, and sandy soils. However, soils with poor drainage should be avoided as they can cause root rot and other diseases.
Cultivation Methods
Diospyros sandwicensis (A. DC.) Fosberg var. rotundata St. John, commonly known as Ka'?persimmon, is a flowering plant native to Hawaii. It can be grown in both tropical and subtropical regions. The plant prefers a sunny location with well-drained soil that has a pH of 6 to 7.5. It can be grown from seeds or cuttings, but cuttings are generally preferred for propagation as they offer more predictable growth.
Watering Needs
Proper watering is essential for the growth and health of the Ka'?persimmon plant. It prefers moderate watering that keeps the soil moist but not too wet. The plant is drought tolerant, but it thrives when watered regularly. In areas with heavy rainfall, it is essential to ensure proper drainage to avoid waterlogging, which may lead to root rot.
Fertilization
Ka'?persimmon requires regular fertilization to grow and produce fruit. A balanced fertilizer with a higher potassium content is recommended for this plant. Fertilizers should be applied during the growing season, typically from March to September. Applying a slow-release granular fertilizer every four months will provide sufficient nutrients for the plant to thrive.
Pruning
Pruning is a critical aspect of Ka'?persimmon cultivation, as it helps maintain the plant's size and shape and ensure optimal fruit production. Pruning should be done in the late winter or early spring before the growing season begins. It involves removing dead or damaged branches and any shoots that grow below the graft union. Ideally, the plant should be kept at a height of 10-12 feet for optimal fruit production.
Propagation of Diospyros sandwicensis var. rotundata
Diospyros sandwicensis var. rotundata, also known as Hawaiian persimmon or Wana, is a species of tree in the family Ebenaceae. It is native to Hawaii and can be propagated through several methods.
Seed Propagation
This species can be propagated by seed, which can be obtained from mature fruit. The seeds should be removed from the fruit and cleaned before sowing. The seeds can be sown in a seed tray filled with a well-draining potting mix. The tray should be kept moist, and the seedlings should emerge within 4 to 6 weeks. Once the seedlings reach a height of 3 to 4 inches, they can be transplanted into larger containers or directly into the field.
Vegetative Propagation
Another method of propagation is through vegetative means, including air layering, grafting, and rooting cuttings. Air layering involves making a small cut in the branch and wrapping it with moist sphagnum moss. The moss is then covered with plastic wrap to create a humid environment that encourages rooting. Once roots develop, the branch can be cut and transplanted into a new container or directly into the field.
Grafting involves joining a scion from a desired cultivar onto a rootstock of the same species. This method allows for the production of consistent fruit quality and is commonly used in commercial production.
Rooting cuttings involves taking a stem cutting from a mature tree and placing it into a rooting hormone. The cutting is then planted in a potting mix and kept moist until roots develop. Once roots develop, the cutting can be transplanted into a larger container or directly into the field.
Propagation through division, where the plant is separated into individual plants, is not recommended for Diospyros sandwicensis var. rotundata, as it is difficult and rarely successful.
Disease Management
Diospyros sandwicensis var. rotundata is generally a disease-resistant plant but can still be affected by some diseases.
Anthracnose is a common disease that affects the leaves and causes small, circular spots that may enlarge and merge, eventually leading to defoliation. To manage this disease, remove all the affected parts of the plant and dispose of them in a sealed bag. Be sure to apply fungicide as per the manufacturer's instructions.
The plant is also susceptible to rust diseases that cause orange to red pustules on the leaves. Rust-causing fungi require moisture to spread, so avoid overhead watering in the late afternoon or evening.
Black spot is another significant disease that can affect the leaves, presenting as black or brown spots with yellowing tissue. Prune the affected leaves and dispose of them, then apply a fungicide. You can prevent black spot by avoiding overhead watering, promoting adequate air circulation, and applying a fungicide proactively.
Pest Management
The most common pest to affect Diospyros sandwicensis var. rotundata is the thrips, which suck the sap and cause the leaves to develop pale blotches. Use sticky traps to help you identify the presence of thrips, prune off the affected leaves, and release natural predators like lady beetles or lacewings.
The plant is also susceptible to mealybugs that suck the sap and weaken the plant's overall health. Prune and dispose of the affected parts of the plant and release natural predators for control, or use insecticidal soap or neem oil.
Spider mites can also be a considerable issue, especially in dry weather conditions. They present as fine webbing on the leaves and cause them to become pale and stippled. Spray the leaves with a forceful stream of water to dislodge the spider mites, and release natural predators like ladybugs. You may also use insecticidal soap or neem oil to manage spider mites.
