Overview: Dubautia arborea (Gray) Keck
Dubautia arborea (Gray) Keck, also known as Hawaiian wood-sorrel, is a flowering plant species that belongs to the family of Asteraceae and is endemic to Hawaii. It is one of the many species of Dubautia, which is a diverse and widespread genus of woody plants in Hawaii. Dubautia arborea is commonly found in the humid to wet forests and subalpine shrublands of Hawaii's higher elevations, particularly on the islands of Maui and Hawaii.
Common Names
The common names of Dubautia arborea include Hawaiian wood-sorrel, tree dubautia, and wood-sorrel tree. In Hawaii, it is also known as ??hi?a lehua kuahiwi, which translates to "mountain ??hi?a lehua", referring to its habitat and the resemblance of its leaves to those of the ??hi?a lehua tree.
Appearance
Dubautia arborea is a small tree that can grow up to 10 meters (33 feet) tall, although it is usually much shorter. It has a slender trunk with a few branches that are covered in fine, reddish-brown hairs. The leaves are arranged spirally along the branches and are about 5 to 20 cm (2 to 8 inches) long. They are oval-shaped with a pointed tip, and have a distinct lemony scent when crushed. The flowers are small and yellow, and are clustered in tight groups at the end of the branches. They bloom from July to September.
Uses
Dubautia arborea has no known medicinal or commercial uses, but its wood is used by native Hawaiians to make decorative items, such as calabashes, bowls, and poi pounders. Its leaves were also traditionally used for medicinal purposes, such as treating cuts and wounds. Today, Dubautia arborea is mostly appreciated for its aesthetic value and is often planted in gardens or used for landscaping. It is also important ecologically as it provides habitat for various native bird species, insects and other creatures who rely on it for food and shelter.
Light Requirements
Dubautia arborea typically grows in areas with full sun exposure. It prefers at least six hours of direct sunlight each day, although it can tolerate partial shade.
Temperature Requirements
This plant is native to the high elevation areas of Hawaii, where temperatures can vary throughout the year. However, it is unable to tolerate frost or temperatures below 50°F for extended periods. Ideally, the temperature range for Dubautia arborea should be between 60 – 75°F.
Soil Requirements
Dubautia arborea prefers well-draining soil with a pH of 5.5 – 6.5. It can tolerate a wide range of soil types, including clay, sandy, or loamy soils. However, it is sensitive to soils with high salt content. The soil should be kept moist, but not waterlogged, as this can lead to root rot.
Cultivation Methods
Dubautia arborea, also known as Dubautia kealiae or Kealia swamp dubautia, is a plant native to Hawaii and has an upright growth habit reaching up to 10 feet tall. The plant thrives in full sun but can also grow in partial shade. The preferred soil for cultivation is well-draining with a slightly acidic pH. When planting the Dubautia arborea, ensure that there is enough space for the plant to grow to its maximum height and width. The plant can be propagated through seeds or cuttings.
Watering Needs
The Dubautia arborea plant requires moderate watering, preferably with well-drained and moist soil. During the growing season, water the plant once or twice every week, depending on the soil type and weather conditions. Avoid overwatering the plant, which can lead to root rot and fungal diseases. During the winter, reduce the watering frequency to once every ten days to allow the soil to dry out slightly.
Fertilization
Fertilization is essential for the healthy growth and development of the Dubautia arborea plant. Use a balanced fertilizer with equal amounts of nitrogen, phosphorus, and potassium. Apply the fertilizer twice a year, during the growing season, once in the spring and once in the fall. Avoid applying too much fertilizer, which can lead to the accumulation of salts in the soil and damage the roots.
Pruning
Pruning is essential for the maintenance and control of the Dubautia arborea plant. The plant's natural growth habit is upright and bushy, meaning that pruning is necessary to maintain its shape. Focus on removing the dead, damaged, or diseased branches and leaves. Prune the plant in the early spring before the growing season begins to allow enough time for new growth. Use clean and sharp pruning tools to avoid damaging the plant. For larger branches, use a pruning saw to make clean cuts to avoid tearing the bark.
Propagation Methods of Dubautia Arborea
Dubautia arborea, commonly known as naenae, is a species of plant endemic to Hawaii. It is a member of the aster family and grows up to a height of 20 feet. Being a popular garden plant and a symbol of Hawaiian culture, it is important to know the different ways one can propagate it to maintain its population. Here are some propagation methods for Dubautia arborea:
Seed Propagation
The easiest and most common method of propagating Dubautia arborea is by seed. The plant produces an abundance of small, light-colored seeds that can be collected and stored for future use. To increase the success of seed germination, stratify the seeds by placing them in a plastic bag filled with damp perlite or vermiculite and leaving them in a refrigerator for a month or two. This will trick the seeds into thinking that they have been through winter and are ready to germinate. Once stratified, plant the seeds in a pot or planting tray filled with a well-draining soil mix, and keep it moist.
Cuttings Propagation
Dubautia arborea can also be propagated by cuttings, which is a faster way to produce clones of the parent plant. Take stem cuttings from the plant in the summer months when the plant is in active growth. Use a sharp, sterile knife to make a diagonal cut and remove all leaves except the top few. Dip the cut end into rooting hormone and plant the cutting in a well-draining soil mix in a pot. Keep the soil moist but not waterlogged, and place the pot in a sheltered, semi-shaded spot. Roots should form within 2-4 weeks, and the new plant can be transplanted into a larger pot or directly into the ground.
Division Propagation
Another method of propagating Dubautia arborea is through division. This is best done in the spring when new growth has just begun. Carefully dig up the parent plant and use a sharp, sterile knife to divide its root ball into sections. Each section should have some young shoots and a good amount of healthy roots. Plant each division immediately in a well-draining soil mix and keep the soil moist but not waterlogged. The new plants will establish in a few weeks and can be transplanted to their permanent position when they have grown enough foliage.
With these propagation methods, you can increase the population of Dubautia arborea and keep its beauty and cultural significance alive.
Disease and Pest Management of Dubautia arborea (Gray) Keck
Dubautia arborea (Gray) Keck is a plant that belongs to the family Asteraceae. Like any other plant, it is susceptible to various diseases and pests. Proper disease and pest management strategies are crucial in maintaining the plant's health and productivity.
Common Diseases
The most common disease that affects Dubautia arborea is caused by a fungus called Phyllosticta dubautiae. This fungus causes leaf spot disease, which is characterized by the appearance of small reddish-brown spots on the leaves. The infection can lead to defoliation and reduced plant growth.
Another prevalent disease that affects Dubautia arborea is root rot. The disease is caused by a fungus called Pythium, which thrives in areas with high soil moisture and poor drainage. The fungus attacks the roots, leading to root decay and eventually plant death.
Disease Management
To manage leaf spot disease, it is advisable to prune infected leaves and remove them from the plant's vicinity. Avoid overhead irrigation to reduce the spread of the disease. In severe cases, you can use fungicides to control the fungus's growth.
To manage root rot disease, it is crucial to improve soil drainage by adding organic matter to the soil. You can also control the spread of the disease by avoiding over-irrigation. In extreme cases, fungicides can also be used to prevent further spread.
Common Pests
The most common pest that attacks Dubautia arborea is the Dubautia beetle (Chrysomelidae). This beetle feeds on the plant's foliage, leading to defoliation and reduced plant growth. The plant's roots are also susceptible to nematode infestation, leading to root decay and eventually plant death.
Pest Management
To control Dubautia beetle, you can handpick and dispose of the beetles or use insecticidal soap sprays. Multiple applications of insecticidal soap may be required for effectiveness. For nematodes, increasing the number of beneficial microbes in the soil, including fungi and bacteria, can significantly reduce nematode populations. Solarization of the soil can also be used to manage nematodes by exposing the soil to high temperatures using plastic covers.
Overall, disease and pest management strategies are crucial in maintaining the health and productivity of Dubautia arborea. Understanding the common diseases and pests and their management approaches can help prevent plant loss and ensure healthy plant growth.
