Overview:
Cyanea holophylla Hbd. var. obovata Rock is a species of plant in the family Campanulaceae.
Origin:
The plant is native to Hawaii, specifically the island of Kauai.
Common names:
This plant is commonly known as "Hawaiian Lobelia" or "Koolau Range Cyanea."
Appearance:
Cyanea holophylla Hbd. var. obovata Rock is a shrub that can grow up to 5 meters tall. The plant's leaves can reach up to 60 centimeters long and 30 centimeters wide. The leaves are bright green and glossy. The plant produces clusters of purple flowers that can reach up to 10 centimeters long.
Uses:
The plant is commonly used in landscaping due to its bright green leaves and unique, showy flowers. In traditional Hawaiian medicine, the plant was used to treat stomach ailments and swelling.
Light
Cyanea holophylla Hbd. var. obovata Rock prefers bright, indirect light. Direct sunlight can cause leaf burn and damage the plant. The plant can also tolerate some shade but may not flower as well in low light conditions.
Temperature
The ideal temperature range for this plant is between 65-75°F (18-24°C). It can tolerate temperatures up to 85°F (29°C) during the day and down to 55°F (13°C) at night. Avoid exposing the plant to extreme fluctuations in temperature as it can stress the plant and cause damage.
Soil
Cyanea holophylla Hbd. var. obovata Rock prefers well-draining soil that is rich in organic matter. A mixture of peat moss, perlite, and regular potting soil can be used. The pH of the soil should be slightly acidic, between 5.5-6.5. Avoid using heavy clay soils or soils that retain too much moisture as it can cause root rot.
Water
The plant likes to be moist but not overly wet. Water the plant when the top inch of soil begins to feel dry. Avoid letting the plant sit in water or become waterlogged. During the winter, reduce the frequency of watering and allow the soil to dry out slightly between waterings.
Fertilizer
Cyanea holophylla Hbd. var. obovata Rock benefits from regular fertilization during the growing season (spring and summer). Use a balanced fertilizer with an NPK ratio of 20-20-20 every two weeks. During the winter, reduce fertilization or stop altogether.
Cultivation Methods
Cyanea holophylla Hbd. var. obovata Rock is a tropical plant that thrives in a moist and humid environment. It is recommended to grow this plant in a pot with a mixture of peat moss and perlite or sand, as this combination provides excellent drainage. The plant prefers bright, indirect sunlight, so placing it near a north-facing window would be ideal.
Watering Needs
Watering frequency is crucial for the growth and health of Cyanea holophylla Hbd. var. obovata Rock. The soil should be kept moist but not waterlogged. Water the plant thoroughly when the soil seems dry to the touch. Frequent misting helps maintain the required humidity levels. In addition, it would be best to use rainwater or distilled water to prevent the buildup of harmful minerals and salts.
Fertilization
Cyanea holophylla Hbd. var. obovata Rock requires nutrients to support its growth. A balanced fertilizer with equal parts of nitrogen, phosphorus, and potassium can be used. Fertilize the plant every two to three months during the growing season, which is usually from early spring to late summer. Be cautious while applying fertilizer, as over-fertilization can result in poor growth or even death of the plant.
Pruning
Pruning is essential to maintain the plant's shape and appearance. It can also help prevent the plant from becoming overly dense and risking disease. Cut off any yellowing or damaged leaves and stems with a clean and sharp pair of scissors or pruning shears. Regular pruning will encourage Cyanea holophylla Hbd. var. obovata Rock to produce new growth and result in a fuller and healthier-looking plant.
Propagation of Cyanea holophylla Hbd. var. obovata Rock
Cyanea holophylla Hbd. var. obovata Rock can be propagated through two methods:
1. Seed Propagation
Seeds of Cyanea holophylla Hbd. var. obovata Rock can be collected from its fruits. The fruiting season is from September to February. Once the fruits have ripened, the seeds can be extracted and sown in a well-draining mix of peat moss and perlite or vermiculite. The seeds should be kept moderately moist and warm, with a temperature between 20-25°C, and germination should occur within 2-3 months. Once the seedlings are big enough to handle, they can be transplanted into individual pots and cared for like mature plants.
2. Vegetative Propagation
Cyanea holophylla Hbd. var. obovata Rock can also be propagated through vegetative means, specifically stem cuttings. Cuttings of about 10-15 cm long can be taken from the mature plant during the growing season and treated with a rooting hormone before being inserted into moist and well-draining rooting media, such as perlite or vermiculite. The cuttings should be kept warm and moist, with a temperature between 20-25°C, and roots should form within 2-3 months. Once rooting has occurred, the cuttings can be transplanted into individual pots.
Disease Management
Cyanea holophylla is susceptible to various fungal, bacterial, and viral diseases. The common diseases that affect this plant are:
- Leaf Spot Disease: It is caused by the fungus Cercospora and results in brown spots on the leaves. To manage this disease, affected plant parts should be removed and destroyed.
- Root Rot: It is caused by the soil-borne fungus Pythium and can lead to plant death. Overwatering and poor drainage are the leading causes of root rot. To manage this disease, reduce watering and improve drainage.
- Powdery Mildew: It is a fungal disease that causes white, powdery growth on the leaves and stems. To manage powdery mildew, you can apply a fungicide or neem oil on the affected plant parts.
Pest Management
Cyanea holophylla may also attract various pests, which can cause significant damage to the plant. The common pests that affect this plant are:
- Aphids: They suck sap from the plant, leading to stunted growth and yellowing of leaves. To manage aphids, you can spray the plant with neem oil or insecticidal soap.
- Mealybugs: They attack the plant by feeding on the sap and secreting a sticky substance called honeydew, which attracts ants. To control mealybugs, wipe the plant's leaves with a cotton swab dipped in alcohol.
- Spider Mites: They cause yellowing and curling of leaves and can kill the plant if left unmanaged. To manage spider mites, you can spray the plant with insecticidal soap or neem oil.
It's essential to inspect the plant regularly to detect and manage any disease or pest infestations as early as possible. This can prevent the spread of disease or pests to other plants and ensure the plant remains healthy.
