Origin
Dubautia kohalae (Skottsberg) St. John is a species of plant in the family Asteraceae. It is endemic to Hawaii and is found only on the island of Hawaii (the Big Island).
Common Names
Dubautia kohalae is commonly known as "Kohala Dubautia" or simply "Kohala silversword".
Uses
The plant has no known uses in traditional medicine or as a food source. However, it plays an important ecological role in the Hawaiian ecosystem as it provides habitat for various native insects and birds. The plant has also gained recognition for its aesthetic appeal, and has been cultivated for ornamental purposes in botanical gardens.
General Appearance
Dubautia kohalae is a small shrub that typically grows to a height of 2-3 feet. It has slender stem and long, narrow leaves that are a distinct silvery-gray color. Its leaves are covered in woolly hairs that help to prevent water loss in dry conditions. The plant produces small, white or pale yellow flowers that bloom in late summer. The flowers are arranged in clusters at the end of the stem, and are surrounded by a ring of sharply pointed bracts. The plant's overall appearance is silvery-gray, making it a striking addition to any garden or natural landscape.
Light Requirements
Dubautia kohalae (Skottsberg) St. John typically grows in full sun to partial shade environments. It thrives in areas where it can receive plenty of light for photosynthesis, and moderate shade periods to reduce water loss. In shaded areas, it will stretch towards the light source and become lanky and less sturdy.
Temperature Requirements
Dubautia kohalae (Skottsberg) St. John is endemic to Hawaii, where it experiences a year-round tropical climate. It favors warm temperatures, between 20-30°C (68-86°F). It is susceptible to frost and freezing temperatures and may die in prolonged colder periods. The ideal temperature range should not vary significantly, or it may hinder the growth and flowering of the plant.
Soil Requirements
Dubautia kohalae (Skottsberg) St. John prefers well-drained, nutrient-rich soil with a slightly acidic pH range (between 5.5-6.2 ). It naturally grows in rocky, volcanic soil in the wild but will grow with equal success in fertile soil in the garden. The plant is tolerant of a wide range of soil textures, such as sandy, loam, or clay soil. The soil should also be kept consistently moist, but not waterlogged, as it hinders the plant's growth and may cause root rot.
Cultivation of Dubautia kohalae (Skottsberg) St. John
Dubautia kohalae (Skottsberg) St. John, commonly known as Kohala Mountain Dubautia, is a rare plant species endemic to Hawaii. To cultivate this plant successfully, several factors are necessary to be considered, including temperature, sunlight, soil quality, and drainage.
Temperature and Sunlight
Dubautia kohalae plants prefer a cool temperature range. Therefore, they tend to grow best in mildly cool habitats. A nighttime temperature of about 50 to 60 ? and a daytime temperature of around 65-75 ? are ideal for optimal growth. Since it is a sun-loving plant, it requires plenty of sunlight but is sensitive to very high temperatures.
Soil Quality and Drainage
The Kohala Mountain Dubautia plant thrives in well-drained soil with a pH range of 6.2 to 7.0. It can tolerate slightly acidic to slightly alkaline soil. You can add an appropriate amount of compost or aged manure to improve the soil's fertility. Additionally, avoid over-watering or watering too frequently as this plant is sensitive to root rot.
Watering Needs
The Kohala Mountain Dubautia plant is water-efficient and can survive in semi-dry conditions. Therefore, you do not need to water the plant regularly. Water the plant when the soil is dry or when the top 1 to 2 inches feels dry to the touch. Items such as gravel or pebbles, or a layer of mulch, can help to retain water in the soil.
Fertilization and Pruning
A steady supply of nutrients is necessary to keep the Kohala Mountain Dubautia plant healthy. To add nutrients to the soil, use a slow-release fertilizer. Pruning is necessary to control the plant's height and shape. It’s also beneficial to remove any dead, underdeveloped, or diseased leaves or branches. Prune this plant after flowering to maintain its attractive shape.
Propagation Methods of Dubautia kohalae (Skottsberg) St. John
Dubautia kohalae, also known as Kohala Mountain Dubautia, is a Hawaii endemic plant species that belongs to the sunflower family. Propagation of Dubautia kohalae can be done through both sexual and asexual methods.
Sexual Propagation
Seeds of Dubautia kohalae can be collected and grown to produce new plants. The seeds can be collected from the plant during the flowering period. Once collected, the seeds must be treated with a fungicide and pre-germination treatment like cold stratification or gibberellic acid. Dubautia kohalae is also capable of self-pollination, but cross-pollination is essential for genetic diversity.
Asexual Propagation
Asexual propagation of Dubautia kohalae can be done through leaf cuttings and stem cuttings. Leaf cuttings can be taken and treated with plant hormones like auxin that promote root formation. Stem cuttings can be taken and planted in a suitable rooting medium like organic compost or peat moss mixed with perlite. Mist propagation or intermittent misting can be done to improve rooting success.
Another asexual propagation method is by division, which involves carefully splitting the parent plant to produce smaller new plants. Division should be done during the growing season, and the cut sites must be treated with a fungicide to prevent infection.
In conclusion, Dubautia kohalae can be propagated both sexually and asexually, providing ample opportunity for its conservation, restoration, and cultivation.
Disease and Pest Management for Dubautia Kohalae
Dubautia kohalae (Skottsberg) St. John, commonly known as Kohala Mountain Dubautia, is a shrub endemic to Hawaii. It prefers cool, moist habitats and is commonly found in montane and subalpine regions. Like any other plant species, Dubautia kohalae is susceptible to diseases and pests. Here’s some information on the common diseases and pests that can affect the plant and ways to manage them:
Common Diseases
Bacterial Leaf Blight: This disease causes water-soaked spots on leaves that turn brown and crispy later. The bacteria responsible for causing blight can spread rapidly in wet weather conditions. One way to manage this disease is by improving air circulation around the plant by regular pruning and disposing of infected leaves.
Ohia Wilt: This is a fungal disease that affects the plant’s roots, causing wilted leaves and dieback. The disease spreads through infected soil and can survive for long periods in soil. One way to manage this disease is by planting resistant varieties or by practicing crop rotation.
Common Pests
Spider mites: These tiny pests can cause significant damage to the plant by sucking fluids from leaves, leading to a yellowish appearance. They thrive in hot, dry conditions and are hard to spot. One way to manage this pest is by using a strong stream of water to knock them off the plant or by using insecticidal soap.
Caterpillars: Caterpillars can damage Dubautia kohalae by feeding on the leaves. They are usually active during the summer season. One way to manage this pest is by handpicking the caterpillars or by using Bacillus thuringiensis.
Aphids: These are small insects that suck sap from plant leaves, leading to wilted leaves. They usually breed rapidly in warm weather. One way to manage this pest is by using a strong stream of water to dislodge them or by using insecticidal soap.
Regular monitoring of the plant’s health is the key to managing diseases and pests effectively. By taking appropriate action early on, one can prevent further damage to the plant.
