Introduction
Metrosideros polymorpha Gaud. ssp. incana (Levl.) Skottsberg, also known as the ‘?hi‘a Lehua tree, is a species of flowering plant that belongs to the myrtle family (Myrtaceae). This tree is native to Hawaii, where it is an important cultural and ecological icon.General Appearance
The ‘?hi‘a Lehua tree is a medium-sized tree that can grow up to 98 feet tall. It has smooth, grayish-brown bark and glossy, dark green leaves that are oval shaped. The tree produces bright red or pink flowers that are shaped like a bottle brush. These flowers bloom between January and May, and they attract many pollinators like bees, birds, and butterflies.Common Names
The ‘?hi‘a Lehua tree is commonly known by different names depending on the region. In Hawaii, it is known as the ‘?hi‘a Lehua or the Lehua tree, while in other parts of the world, it is known as the Hawaiian Metrosideros, Ironwood, or simply as the Ohia tree.Uses
The ‘?hi‘a Lehua tree has many uses, both culturally and ecologically. The wood of the tree is used for various purposes, such as making bowls, canoes, and tools. The flowers are commonly used in Hawaiian lei making, and they hold a significant cultural significance in Hawaiian folklore, where they represent love, beauty, and new beginnings. Ecologically, the ‘?hi‘a Lehua tree serves as an important habitat for many native birds, insects, and other animals. In conclusion, the ‘?hi‘a Lehua tree is a beautiful and important tree that plays a significant role in the culture and ecology of Hawaii. Its striking appearance and cultural significance make it a beloved symbol of the Hawaiian islands.Typical Growth Conditions of Metrosideros polymorpha subspecies incana
Metrosideros polymorpha subspecies incana, commonly known as the silver-barked ironwood, is a tree endemic to Hawaii, specifically in high elevations on the islands of Maui and Hawaii. Here are the typical growth conditions required for this plant species:
Light Conditions
Metrosideros polymorpha subspecies incana requires full sun exposure to thrive. It is adapted to grow in high elevations with intense sunlight and limited cloud cover. Therefore, it is best to plant this species in full sunlight to ensure optimal growth. In areas with low light levels or shaded areas, growth will be severely hindered.
Temperature Conditions
The temperature requirements of Metrosideros polymorpha subspecies incana are critical to its growth and survival. It grows well in a subalpine environment with cool and moist conditions ranging between 45°F and 68°F (7°C to 20°C). Mature trees can tolerate freezing temperatures down to 30°F (-1°C), while young saplings may require frost protection until reaching three years of age.
Soil Requirements
Metrosideros polymorpha subspecies incana requires specific soil conditions to grow properly. It prefers well-drained, acidic soils that are low in organic matter. The ideal soil pH should range from 4.5 to 6.5 to encourage optimal growth. In addition, this species is sensitive to soil compaction, so it is crucial to avoid soil disturbances around the root zone. When planting this species in a garden, it is advisable to mix the soil with compost and organic matter to improve soil structure and fertility.
Cultivation Methods
Metrosideros polymorpha Gaud. ssp. incana (Levl.) Skottsberg, commonly known as the Hawaiian tree, can be grown outdoors. These trees usually prefer the cooler temperatures in high altitude areas and prefer well-drained soils. It is recommended that the plants get at least six hours of full sunlight to grow healthy and strong. The plant can grow up to 20 feet, so it is necessary to provide adequate space when choosing a planting location.
Watering Needs
The Hawaiian tree has moderate water requirements. It is recommended to water the plant only when the soil is dry and not keep the soil wet for an extended period. Overwatering can lead to root rot, drought stress, and leaf wilt. Avoid watering the plant on leaves and flowers, as it can result in the development of fungus and infections.
Fertilization
The plant responds well to fertilization when the appropriate nutrients are applied. A well-balanced fertilizer containing nitrogen, potassium, and phosphorus, with a ratio of 3:1:2, is ideal. It is recommended to use slow-release fertilizers for better absorption. During the growing season, fertilize the plant every four to six weeks. Once the growing season is over, reduce fertilizing the plant, as it can cause growth and foliage burnout.
Pruning
To keep the Hawaiian tree healthy, pruning is essential. It is recommended to prune the plant after flowering to avoid any damage to buds forming for the next season. The best time for pruning is during the dry season. Remove damaged, dead, and weak branches, as they can attract pests and diseases. The branches that are rubbing or crossing over each other should also be removed. To avoid any injuries to the plant, use sterilized pruning tools.
Propagation of Metrosideros polymorpha Gaud. ssp. incana (Levl.) Skottsberg
Metrosideros polymorpha Gaud. ssp. incana (Levl.) Skottsberg, also known as the Hawaiian tree, is a shrub or small tree native to Hawaii. It is commonly propagated by seeds or cuttings.
Propagation by seeds
Propagation by seeds is easy, but it takes a longer time to establish the plant. The seeds are collected from mature fruits and should be sown immediately. The seeds need to be stratified before sowing by keeping them in the cold and moist environment for several weeks. The stratification process breaks the seed dormancy and enhances germination. The seeds can be sown directly in the field or in pots. The soil should be well-drained and fertile. The seeds should be lightly covered with soil and kept moist until germination.
Propagation by cuttings
Propagation by cuttings is quicker and easier than by seeds. The cuttings are collected from mature woody stems of the plant. The cuttings should be about 6-8 inches long and have at least two nodes. The lower leaves should be removed, and the stem should be dipped in a rooting hormone. The cuttings can be grown in pots or in a propagation bed with well-draining soil. The soil should be kept consistently moist until rooting occurs. The rooted cuttings can be transplanted to their permanent location when they have developed a good root system.
Disease Management
Metrosideros polymorpha Gaud. ssp. incana (Levl.) Skottsberg is a relatively disease-resistant plant. However, it may face certain diseases that can affect its growth and health.
One such disease is the Ohia wilt, which is caused by a fungus called Ceratocystis lukuohia. This disease can be managed by avoiding soil disturbance around the roots of the plant and minimizing injuries to the stem. Additionally, removing and destroying infected plants and pruning tools can also help prevent the spread of the disease.
The other disease that can affect Metrosideros polymorpha is the myrtle rust, caused by the fungus Puccinia psidii. This disease produces rust-colored spots on the leaves and can ultimately lead to defoliation and death of the plant. To manage this disease, infected plant material should be removed and destroyed, and the area should be kept free of debris. It is also important to avoid planting susceptible plants in areas where myrtle rust is prevalent.
Pest Management
Similar to diseases, Metrosideros polymorpha Gaud. ssp. incana (Levl.) Skottsberg may face certain pests that can harm it.
The two most common pests that can affect this plant are the Hawaiian bettle and the lobate lac scale. The Hawaiian beetle can cause defoliation of the plant, leading to stunted growth and reduced flower production. On the other hand, the lobate lac scale feeds on the sap of the plant, causing yellowing of the leaves and diminished plant vigor.
To manage these pests, physical removal, handpicking, and insecticidal sprays can be used. Furthermore, encouraging natural predators such as ladybird beetles and green lacewings can also be helpful in controlling the population of these pests.
