Origin
Dubautia scabra (DC.) Keck ssp. leiophylla (Gray) G.D. Carr, commonly known as the Mauna Kea silversword, is a rare plant species endemic to Hawaii. It is found exclusively on the high-altitude volcanic slopes of Mauna Kea on the Big Island.
Common Names
The plant is commonly known by several names including Mauna Kea silversword, hoary silversword, and pua‘ala.
Appearance
Dubautia scabra is a striking perennial plant that can grow up to 1 meter tall. It has a rosette growth habit and features silver-green leaves covered in dense, silky hairs that give the leaves a velvety texture. The leaves are narrow, linear, and strap-shaped, and can grow up to 30 cm long. In the summer months, the plant produces a cluster of lavender-pink flowers on a tall stem, which can grow up to 1 m above the foliage. The flowers are tubular, about 2 cm long, and attract pollinators such as bees and butterflies.
Uses
The Mauna Kea silversword holds great cultural significance in Hawaiian mythology and is regarded as a sacred plant by the local people. Due to its rarity and unique beauty, the plant has become a popular tourist attraction, drawing visitors from all over the world to view it in its natural habitat. However, because of its vulnerability to habitat destruction and climate change, the plant is now protected by law, and visitors are not allowed to touch or remove it.
Light conditions
Dubautia scabra ssp. leiophylla is a sun-loving plant that requires full sunlight exposure to thrive. It grows well in open areas with minimal shade. The plant is adapted to growing in high altitude regions with intense sunlight, so it can tolerate high levels of UV radiation.
Temperature requirements
Dubautia scabra ssp. leiophylla is native to the Hawaiian islands, where it grows in cool and wet mountain forests. The plant is adapted to a temperate climate, with daytime temperatures ranging from 60 to 75°F and nighttime temperatures ranging from 40 to 55°F. It is capable of tolerating brief periods of frost but does not survive prolonged exposure to freezing temperatures.
Soil requirements
Dubautia scabra ssp. leiophylla grows best in well-draining soil that is high in organic matter. In nature, the plant is commonly found in volcanic soils, which are typically nutrient-poor but highly porous and well-drained. The plant is adapted to growing in low-pH soils with a pH range of 4.5 to 6.0. It cannot tolerate waterlogged soils or soils with high salinity levels.
Cultivation Methods
Dubautia scabra ssp. leiophylla is a plant native to Hawaii that thrives in well-draining soil, preferably composed of volcanic ash and cinder. These plants prefer full sun and can tolerate a wide range of temperatures, from high elevations to coastal areas. They require minimal maintenance and are easy to grow, making them ideal for beginners.
Watering Needs
The watering requirements for these plants are low to moderate. These plants have a natural resistance to drought and therefore do not need frequent watering. However, young plants need to be watered more frequently than mature plants to establish their root systems. These plants also prefer to be misted periodically to maintain proper humidity levels.
Fertilization
Dubautia scabra ssp. leiophylla can benefit from occasional fertilization during growth periods. Use a balanced fertilizer with equal amounts of nitrogen, phosphorus, and potassium, which can be applied every three months. Be careful not to overfertilize, as this can lead to excessive growth and reduce the plant's resistance to pests and diseases.
Pruning
Pruning is not necessary for these plants, but some gardeners prefer to shape their plants to maintain a compact and tidy appearance. Prune away any dead or damaged leaves or branches as they appear to promote new growth. However, be careful not to prune too much at one time, as this can shock the plant and impede its growth.
Propagation of Dubautia Scabra ssp. Leiophylla
Dubautia scabra ssp. leiophylla is usually propagated through seeds, cuttings, and division.
Seed Propagation
Seeds of Dubautia scabra ssp. leiophylla can be collected when they are fully matured. They can be sown after collecting in a well-prepared seedbed in a greenhouse or outdoor bed, preferably during spring or summer. The seedbed soil should be moist, free-draining, and rich in organic matter. The seeds should be sown thinly on the substrate and then covered with a thin layer of soil. They should be kept moist but not waterlogged until germination occurs. Seedlings can be transplanted to individual pots or permanent locations after 4-6 weeks of growth and development.
Cutting Propagation
Dubautia scabra ssp. leiophylla can be propagated by stem cuttings taken during the early spring or summer. The cuttings should be about 8-12 cm long and should be taken from healthy parent plants. The basal leaves should be removed, and the cuttings should be dipped in rooting hormone before planting. The cuttings should be planted in a well-draining mix of peat and sand or perlite. The planting pots should be covered with a plastic bag or kept in a propagator to maintain high humidity. The cuttings should be watered only when necessary, and they can be transplanted after root formation, which usually takes 3-4 weeks.
Division Propagation
Dubautia scabra ssp. leiophylla can also be propagated by division during the spring or early summer. The parent plant should be dug out, and the roots should be carefully separated into small sections. Each section should have a healthy clump of leaves and roots. These sections can be then planted in well-prepared beds or pots filled with a suitable potting mix. The soil should be kept moist until the plants are established and start showing new growth.
Disease Management
The plant Dubautia scabra (DC.) Keck ssp. leiophylla (Gray) G.D. Carr can be susceptible to fungal and bacterial diseases. Two common fungal diseases that may affect this plant are powdery mildew and leaf spot. Powdery mildew can cause white or gray powdery spots on the leaves, while leaf spot can cause small brown or black spots on the leaves.
To manage powdery mildew, it is recommended to remove affected plant parts and dispose of them properly. Avoid overhead watering and instead water at the base of the plant to minimize moisture on the leaves. A fungicide can also be applied to control the spread of the disease.
To manage leaf spot, remove affected plant parts and dispose of them properly. Water the plant at the base and avoid getting water on the leaves to minimize moisture. A fungicide can also be applied to control the spread of the disease.
Pest Management
The plant Dubautia scabra (DC.) Keck ssp. leiophylla (Gray) G.D. Carr can also be susceptible to pest infestations. Two common pests that may affect this plant are spider mites and aphids. Spider mites are tiny pests that can produce webs on the leaves, while aphids are small insects that can cause yellowing and distortion of the leaves.
To manage spider mites, consider using a miticide or insecticidal soap. It is also recommended to remove affected plant parts and dispose of them properly. Additionally, consider increasing the humidity levels around the plant, as spider mites thrive in dry environments.
To manage aphids, consider using insecticidal soap or neem oil. It is also recommended to remove affected plant parts and dispose of them properly. Natural predators such as ladybugs can also be introduced to help control aphid populations.
