Origin
Dubautia knudsenii Hbd. ssp. nagatae (St. John) G.D. Carr, commonly known as Nagata's Dubautia, is an endemic Hawaiian plant species. It is found only in Hawaii, in the Hual?lai and Mauna Loa regions of the Big Island.
Common Names
Aside from Nagata's Dubautia, this plant is also known as Knudsen's Dubautia, Dubautia, and Hawaiian Dubautia.
Uses
Being a rare and endemic species, Nagata's Dubautia has no known traditional or cultural uses. It is, however, an important species for conservation due to its endangered status and unique ecological role.
General Appearance
Nagata's Dubautia is a shrub that can reach up to 3 meters in height. It has numerous branches that grow in upright and spreading habit, forming a rounded to broadly columnar bush. Its leaves are elliptic to oblanceolate, measuring around 2-10 cm long and 0.5-1.5 cm wide, with pointed tips and smooth margins. The upper surface of the leaves is bright green, while the undersides are paler and fuzzy. The plant produces clusters of small yellow flowers (around 1 cm in diameter) that grow terminally on the branches from September to December. Nagata's Dubautia is typically found growing in subalpine dry shrublands and dry to mesic forests in volcanic or basaltic soil.
Light Requirements
Dubautia knudsenii Hbd. ssp. nagatae (St. John) G.D. Carr prefers full sunlight to partial shade. It is not tolerant of heavy shade and may not flower well when grown under such conditions.
Temperature Requirements
This plant is adapted to a subalpine climate, with temperatures ranging from 45°F to 65°F. It can withstand light frost and snow but does not tolerate extreme heat. If grown in areas with high temperatures, it may require regular watering to maintain its growth and prevent wilt.
Soil Requirements
The Dubautia knudsenii Hbd. ssp. nagatae (St. John) G.D. Carr prefers well-drained, moist soils with a pH between 5.5 and 6.5. It does not tolerate waterlogged soil and may struggle to grow in heavy clay soils that retain water. Adding organic matter to the soil can help improve its drainage and fertility.
Cultivation methods for Dubautia knudsenii Hbd. ssp. nagatae (St. John) G.D. Carr:
Dubautia knudsenii Hbd. ssp. nagatae (St. John) G.D. Carr is a rare and endangered plant species endemic to Hawaii. It's a subshrub that usually grows up to 1 meter tall. To cultivate Dubautia knudsenii Hbd. ssp. nagatae, you need to recreate its native habitat as much as possible. The plant prefers well-drained soils, moderate temperatures, and moderate humidity. You can grow it in containers or in the ground.
Watering needs for Dubautia knudsenii Hbd. ssp. nagatae (St. John) G.D. Carr:
Dubautia knudsenii Hbd. ssp. nagatae (St. John) G.D. Carr prefers slightly moist soil. Water the plant once a week, or more frequently during hot and dry seasons. Avoid overwatering, as excessive water may lead to root rot. The plant grows naturally in areas with regular rainfall, so it's adapted to occasional droughts.
Fertilization for Dubautia knudsenii Hbd. ssp. nagatae (St. John) G.D. Carr:
Dubautia knudsenii Hbd. ssp. nagatae (St. John) G.D. Carr doesn't require much fertilizer. Apply a balanced fertilizer with an N-P-K ratio of 10-10-10 every three months, or use a slow-release fertilizer once per year. Don't apply fertilizer during the plant's dormant season, which is from late fall to early spring.
Pruning for Dubautia knudsenii Hbd. ssp. nagatae (St. John) G.D. Carr:
Dubautia knudsenii Hbd. ssp. nagatae (St. John) G.D. Carr doesn't require much pruning. Remove any dead, diseased, or damaged stems and leaves as soon as you notice them. You can also prune the plant to maintain its shape or size, but be careful not to remove too much of the plant, as this may affect its overall health. Prune during the plant's growth season, which is from early spring to late summer.
Propagation of Dubautia knudsenii Hbd. ssp. nagatae (St. John) G.D. Carr
Dubautia knudsenii Hbd. ssp. nagatae (St. John) G.D. Carr is a Hawaiian plant that belongs to the sunflower family. It is an endangered plant species due to habitat loss and invasive species. To maintain this species, it is important to propagate it both in the wild and in nurseries.
Propagating Dubautia knudsenii Hbd. ssp. nagatae from Seeds
The best time to collect the seeds of Dubautia knudsenii Hbd. ssp. nagatae is during the months of August to November. It is important to collect the mature seeds that are brown in color. The best way to collect the seeds is by clipping the flower heads and storing them in paper bags until the seeds are ready for collection. Once collected, the seed should be cleaned and stored in a cool, dry place.
Before sowing the seeds, they should be stratified by storing them in the refrigerator for at least one month. The seeds can then be sown in potting soil and covered with a thin layer of sand. The pots should be kept in a humid environment with a temperature range of 68 to 75°F. After the seedlings have sprouted, they should be transplanted into larger pots.
Propagating Dubautia knudsenii Hbd. ssp. nagatae from Cuttings
Propagation through cuttings is also possible for Dubautia knudsenii Hbd. ssp. nagatae. The best cuttings are those that are taken from new growth. The cuttings should be 4-6 inches long, with the lower leaves removed, leaving only two or three at the top. The cuttings can then be dipped in rooting hormone and planted in a well-draining potting mix.
The cuttings should be kept in an area with low light and high humidity. They should not be exposed to direct sunlight or strong winds. The temperature should be kept between 68 and 75°F. Once the roots have developed, the cuttings can be transplanted to larger pots and grown until they are ready for transplantation into the wild.
Propagation of Dubautia knudsenii Hbd. ssp. nagatae is an important conservation measure to ensure the survival of this endangered species.
Disease Management
Dubautia knudsenii Hbd. ssp. nagatae (St. John) G.D. Carr is susceptible to a few common fungal diseases, such as powdery mildew, leaf spot, and rust. These diseases can affect the plant's growth and produce unsightly foliage. To manage fungal diseases, it is advisable to apply fungicides that contain copper or sulfur compounds. Spraying the fungicides on the leaves, stems, and flowers can help prevent future infection. It is also recommended to remove and discard infected plant parts, as they can harbor spores that can reinfect the entire plant. Other cultural practices that can help maintain plant health include proper watering, avoiding overhead watering, and providing adequate ventilation to reduce humidity levels.
Pest Management
Dubautia knudsenii Hbd. ssp. nagatae (St. John) G.D. Carr is not commonly affected by pests. However, aphids, spider mites, and thrips can attack the plant's leaves and cause stunted growth and deformation. To manage pests, a simple method is to wash the leaves with water or apply insecticidal soap or oil to control the infestation. Biological control methods such as introducing predaceous insects, parasitic wasps, or mites can also help control pests. Care should be taken when using chemicals to avoid causing harm to beneficial insects such as pollinators and natural predators.
