Origin and Common Names
Dubautia linearis (Gaud.) Keck ssp. hillebrandii (Mann) G.D. Carr is a plant species from the Asteraceae family. This plant is endemic to Hawaii and can be found on the islands of Maui, Kaho’olawe, and possibly Moloka’i. Dubautia linearis ssp. hillebrandii is commonly known as Hillebrand’s Dubautia or Mauna Kea Dubautia, named after the German physician and botanist William Hillebrand who collected plant specimens in Hawaii during the 19th century.General Appearance
Dubautia linearis ssp. hillebrandii is a perennial herb or shrub that can grow up to 1.5 meters tall. The leaves are linear, narrow, and somewhat fleshy, measuring up to 10 centimeters long and 3 millimeters wide. The plant produces densely packed flower heads that are 1-1.5 centimeters wide, with white ray flowers and yellow disc flowers in the center. The flowers bloom from June to October. Dubautia linearis ssp. hillebrandii is adapted to live in harsh conditions, such as volcanic slopes and high-elevation habitats, with variable temperatures, strong winds, and limited water supply.Uses
Dubautia linearis ssp. hillebrandii has cultural significance in Hawaiian folklore and is associated with the summit of Mauna Kea, a sacred mountain in Hawaiian culture. The plant's leaves and flowers have been used in traditional Hawaiian medicine to treat various diseases and ailments, such as infections, inflammation, and headaches, among others. Due to its rarity and limited distribution, Dubautia linearis ssp. hillebrandii is also of conservation concern and is listed as an endangered species. The plant faces several threats, including habitat loss and degradation caused by invasive species and human activities, as well as climate change and natural disasters. Various conservation efforts are being undertaken to protect and restore the species and its habitat.Light Requirements:
Dubautia linearis (Gaud.) Keck ssp. hillebrandii (Mann) G.D. Carr typically grows in full sunlight or partially shaded areas. It can thrive in areas with high light intensity as long as it is not overly exposed to UV radiation.
Temperature Requirements:
The plant prefers temperatures that range between 10°C and 21°C. Growth is typically optimal in areas with a temperature range between 12°C and 15°C. It is adapted to temperatures that do not vary significantly throughout the year and can tolerate temperatures as low as 0°C for a short period.
Soil Requirements:
Dubautia linearis (Gaud.) Keck ssp. hillebrandii (Mann) G.D. Carr requires well-drained soil that is slightly acidic. The plant can grow in various soil types, including loam and sandy soils. However, the soil must contain sufficient levels of essential nutrients required for growth such as nitrogen, phosphorus, and potassium. High soil salinity levels can affect the plant's growth and development.
Cultivation Methods
Dubautia linearis (Gaud.) Keck ssp. hillebrandii (Mann) G.D. Carr is a native Hawaiian plant that adapts well to cultivation in a garden setting. It thrives in well-draining soil, and it requires full sun or partial shade. Before planting, improve soil drainage by adding sand or small rocks to the soil. A pH range of 5.5 to 6.5 is ideal for growing Dubautia linearis, and ideally, the soil should be slightly acidic.Watering Needs
Dubautia linearis (Gaud.) Keck ssp. hillebrandii (Mann) G.D. Carr requires regular watering during the dry season. Its soil should be kept moist but not waterlogged. Watering every three days during the summer works well. In the winter, reduce watering to once every seven to ten days, mimicking local rainfall patterns. Watering should be reduced as the plant matures.Fertilization
Dubautia linearis (Gaud.) Keck ssp. hillebrandii (Mann) G.D. Carr does not require much fertilizer. It can do well with minimal fertilization or none at all. However, a liquid fertilizer once a month, a balanced 10-10-10 commercial fertilizer, can be applied. Dilute the fertilizer and apply only to the soil around the plant, and avoid getting it directly on the leaves.Pruning
Dubautia linearis (Gaud.) Keck ssp. hillebrandii (Mann) G.D. Carr does not require much pruning. However, removing any damaged or dead leaves or stems can help improve the growth of the plant. Gently cut them off with pruning shears. Do not prune too much off the plant, as it can cause stress and make it more susceptible to diseases. Any pruning should be during the growing season.Propagation Methods of Dubautia linearis (Gaud.) Keck ssp. hillebrandii (Mann) G.D. Carr
Dubautia linearis (Gaud.) Keck ssp. hillebrandii (Mann) G.D. Carr is a plant that belongs to the Asteraceae family, endemic to the island of Oahu, Hawaii. This species is also known as Hillebrand’s Dubautia. It is a shrub that can grow up to 6 feet tall and can live for 30 years. The species has a low seed set which makes natural propagation difficult. As a result, vegetative propagation is preferred. The plant is propagated by stem cuttings or root division.
Propagation by Stem Cuttings
The stem cuttings should be taken from the current season's growth that is from the growing tips of the plant. The cuttings should be at least 3 to 4 inches long and should be removed using a sharp and clean pair of pruners. The lower leaves are removed, and the remaining top leaves are cut in half to reduce moisture loss. The cuttings are then planted in a moist soil mixture of peat moss and perlite or sand. The cuttings should be kept in indirect light with high humidity and the soil should be kept moist but not waterlogged. The cuttings should root in 6 to 8 weeks, and after 4 to 6 months, they can be transplanted into individual pots.
Propagation by Root Division
Root division is another method of propagating Dubautia linearis (Gaud.) Keck ssp. hillebrandii (Mann) G.D. Carr. The root division should be done in early spring or fall when the plant is not actively growing. The parent plant is carefully uprooted and the roots are separated into individual sections. Each section should have sufficient roots, preferably with at least five leaves. The sections are then planted in a moist soil mixture of peat moss and perlite or sand. The plants should be kept in indirect light with high humidity and the soil should be kept moist but not waterlogged. The newly propagated plants should be kept in their pots until they have developed a strong root system and have grown to a larger size.
Propagation of Dubautia linearis (Gaud.) Keck ssp. hillebrandii (Mann) G.D. Carr should be done with care to avoid damage to the parent plant. The propagated plants should be protected from direct sunlight, wind, and rain until they have established a strong root system. With proper care and attention, the newly propagated plants should grow into healthy mature plants.
Disease Management
Dubautia linearis (Gaud.) Keck ssp. hillebrandii (Mann) G.D. Carr is a relatively disease-resistant plant, but there are some pests and diseases it may be vulnerable to. One common disease that can affect this plant is powdery mildew, which is a fungal disease that can cause a white, powdery coating to develop on the leaves. One way to manage powdery mildew is to prune affected leaves and increase air circulation around the plant.
Another fungal disease that can impact this plant is rust. Rust appears as yellow to orange-red spots on the leaves, which can later become brown as the infected tissue dies. A preventative measure to manage rust is to create a healthy growing environment by minimizing the amount of moisture around the plant. Fungicidal sprays can also be used to control the disease.
Pest Management
Like many plants, Dubautia linearis (Gaud.) Keck ssp. hillebrandii (Mann) G.D. Carr can be susceptible to insect pests such as aphids. Aphids are small, soft-bodied insects that can suck the sap from the leaves, resulting in curled or distorted foliage. Applying insecticidal soap or neem oil to the plant can help control the aphid infestation.
Whiteflies, another insect pest, are small, white flies that can also feed on the plant's sap, causing the leaves to yellow and wither. To control whiteflies, releasing natural predators such as ladybugs and lacewings can help keep their populations in check. Yellow sticky traps can also be used to catch adult whiteflies.
Caterpillars can also be a problem for this plant. The larvae of moths and butterflies, caterpillars can consume large amounts of foliage, causing significant damage to the plant. Handpicking caterpillars from the plant is an effective control method, or microbial insecticides, such as Bacillus thuringiensis, can be applied to manage caterpillar infestations.
