Origin and Common Names
Metrosideros polymorpha Gaud. ssp. glaberrima (Levl.) Skottsberg, also known as the smooth-leaved '?hi'a, is a species of flowering tree that is endemic to the Hawaiian Islands. Its common names include '?hi'a lehua, 'aiea, and 'a'lehua. This plant is a member of the myrtle family (Myrtaceae) and is one of the most common and important native plant species found throughout the Hawaiian Islands.
General Appearance
The smooth-leaved '?hi'a tree can grow up to 23 meters in height and can have a trunk diameter of up to one meter. It has a broadly conical or rounded crown, with foliage that is medium green and glossy. The leaves of this plant are ovate to elliptic in shape and can grow up to 10 centimeters long. One unique feature of the smooth-leaved '?hi'a tree is its beautiful and showy flowers, which are presented in large, dense clusters that can range in color from bright red to pink, orange, and yellow.
Uses
The smooth-leaved '?hi'a tree has been an important cultural symbol and resource for Hawaiian people for centuries. According to Hawaiian folklore, the '?hi'a tree is sacred to the fire goddess Pele, and its flowers are linked to love and passion in Hawaiian poetry and legends. The wood of the tree is strong and durable, and was traditionally used to construct canoes, tools, and furniture. Today, the smooth-leaved '?hi'a tree is highly valued for its ornamental and ecological qualities, and is commonly planted in gardens and landscaping throughout the Hawaiian Islands and other tropical regions around the world.
Light Requirements
Metrosideros polymorpha ssp. glaberrima requires full sun exposure to grow and thrive. It is commonly found growing in sunny open spaces such as rocky cliffs and dry soils. Areas with partial shade may also be suitable, but it is crucial to ensure that the plant receives at least six hours of direct sunlight each day.
Temperature Requirements
The plant grows well in warm and humid conditions. The ideal temperature range for Metrosideros polymorpha ssp. glaberrima growth is between 20 to 30°C (68-86°F) during the day and 16-21°C (60-70°F) at night. However, the plant has been observed to survive in temperatures as low as 10°C (50°F).
Soil Requirements
The plant prefers well-draining soils with a slightly acidic to neutral pH of 5.5 to 7.0. It can grow in a variety of soil types, from sandy to clayey soils, as long as they are well-draining. The plant likes a moderately fertile soil and responds well to soil amendments such as compost or organic matter. However, it can also tolerate nutrient-poor soils and is often found growing in volcanic soils.
Cultivation Methods
Metrosideros polymorpha Gaud. ssp. glaberrima (Levl.) Skottsberg, also known as the smooth-barked form of 'ohi'a lehua, can be cultivated through seeds, cuttings, or by transplanting a young plant. Seedlings require well-draining soil and should be kept in a partially shaded area until they grow bigger. Once they are established, they can be moved to a spot with full sun exposure. Cuttings can be taken from semi-hardwood growth, placed in a rooting hormone and planted in a well-drained potting mix. Once roots have formed, they can be transplanted. Transplanting young plants needs to be done carefully, ensuring that the roots are not damaged during the process.
Watering Needs
Metrosideros polymorpha Gaud. ssp. glaberrima needs regular watering, especially during the dry season. It is important to water the plants deeply, enough to soak the soil up to the root zone. The watering frequency may depend on various factors, such as soil type, temperature, humidity, and rainfall. In general, it is recommended to water the plant every three to four days. However, it is important to monitor the soil moisture and adjust the watering schedule accordingly. During heavy rainfall, it is advisable to avoid watering as this can lead to waterlogging and damage to the plant's root system.
Fertilization
Regular fertilization is necessary to promote healthy growth and beautiful blooms of Metrosideros polymorpha Gaud. ssp. glaberrima. A balanced fertilizer with an N-P-K ratio of 10-10-10 is recommended. Fertilizer can be applied every two to three months during the growing season. A slow-release fertilizer can also be used, which releases nutrients gradually over time. It is important to avoid over-fertilizing, as this can lead to excessive vegetative growth and poor flowering.
Pruning
Pruning is essential to maintain the size and shape of Metrosideros polymorpha Gaud. ssp. glaberrima. Pruning should be done during the dormant season when the plant is not actively growing. It is important to remove any dead, damaged, or diseased branches. Pruning can also be used to thin out dense growth, which encourages better air circulation and sunlight penetration. To promote more blooms, it is recommended to prune the plant lightly after each flowering cycle.
Propagation Methods for Metrosideros polymorpha Gaud. ssp. glaberrima (Levl.) Skottsberg
Metrosideros polymorpha Gaud. ssp. glaberrima (Levl.) Skottsberg, commonly known as the "Hawaiian Christmas berry," is a plant that is endemic to the Hawaiian Islands. Propagation of this plant can be done using different methods, including:
Seed Propagation
The easiest and most common propagation method for Metrosideros polymorpha Gaud. ssp. glaberrima is through seeds. This plant produces small, black seeds that can be collected from the fruit capsules when they turn brown and start to open. After collection, the seeds should be soaked in water for 24 hours to soften the seed coat and improve germination.
Once the seeds are ready, they should be sown in a well-draining potting mix and covered with a thin layer of soil. The pot should be kept moist, but not waterlogged, and the temperature should be maintained at around 60-70 °F to encourage germination.
Cuttings Propagation
Another propagation method that can be used for Metrosideros polymorpha Gaud. ssp. glaberrima is vegetative propagation using stem cuttings. This method involves taking stem cuttings from mature, healthy plants and rooting them in a suitable medium.
The cuttings should be taken during the dormant season, and the lower leaves should be removed before planting. They should then be planted in a well-draining rooting medium and kept moist in a humid environment. The cuttings should start to root within four to six weeks, and they can be transplanted into pots or directly into the soil once they have established roots.
Air Layering Propagation
Another propagation method that can be used for Metrosideros polymorpha Gaud. ssp. glaberrima is air layering. This method involves inducing the plant to form roots on a stem that is still attached to the mother plant.
To do this, a section of the stem is selected, and a ring of bark is removed from around it. The exposed area is then covered with a rooting hormone and moist sphagnum moss, which is then wrapped with plastic. Once roots have formed, the new plant can be separated from the mother plant and planted in a new location.
Overall, Metrosideros polymorpha Gaud. ssp. glaberrima can be propagated through multiple methods, allowing for easy expansion of this unique Hawaiian plant species.
Disease and Pest Management for Metrosideros Polymorpha Gaud. Ssp. Glaberrima (Levl.) Skottsberg
Metrosideros Polymorpha Gaud. ssp. Glaberrima (Levl.) Skottsberg, commonly known as '?hi'a Lehua, is a species of flowering evergreen tree endemic to Hawai’i. It is an important plant species for the Hawaiian ecosystem due to its ability to regulate watersheds, provide habitat for endemic wildlife, and its cultural significance. However, like any other plant species, it is susceptible to various diseases and pests that can affect its growth and survival.
Common Diseases and their Management
Rapid ??hi?a Death (ROD)
ROD is a fungal disease caused by two strains of the Ceratocystis fungi - C. huliohia and C. lukuohia. The disease can kill an ?hi'a tree within a few days or weeks. The fungus attacks the tree’s vascular system, causing the tree to wilt and die. To manage the spread of the disease, avoid injuring ?hi'a trees as it opens an entry point for the fungus.
Canker
Cankers are caused by fungal infections that penetrate through wounds or natural openings in the plant. Symptoms include the development of sunken lesions, browning of the bark, and wilting of the leaves. Prune out infected branches and dispose of them far from the vicinity of the plant. Promote good drainage and avoid overhead watering. Fungicides that contain copper can also be applied.
Common Pests and their Management
Hawaiian Beetles
The ??hi?a tree is a common host for Hawaiian beetles, such as Ambrosia beetles and long-horned beetles, and their larvae. These beetles tunnel into the tree's wood, causing damage to the tree's vascular system. Clearing the area around the tree can reduce the chances of beetle infestation, while insecticides containing permethrin or carbaryl can be used to kill existing beetles. Regularly pruning the tree can also help expose beetle larvae and remove them from the tree.
Caterpillars
The ??hi?a tree is commonly infested by the caterpillars of the Hawaiian Eupithecia moth, which feeds on the leaves. Regular pruning and maintaining a clean canopy reduces the chances of moth infestations. Insecticides containing Bacillus thuringiensis can also be effective against caterpillars.
In conclusion, managing diseases and pests is essential for ?hi'a trees to thrive in their natural environment. Preventive measures such as regular inspection, pruning, clearing the area around the tree, and avoiding tree injuries are some of the steps that can reduce the chances of diseases and pests infestations. Applying suitable insecticides and fungicides can also help control the spread of pests and diseases.
