Origin and Common Names
Pittosporum tenuifolium Gaertn., also commonly known as Kohuhu, tawhiwhi, or black matipo, is an evergreen shrub or small tree that is native to New Zealand.
General Appearance
The Pittosporum tenuifolium Gaertn. plant can grow up to 10 meters in height and 3 meters in width. It has a dense and bushy habit, with dark green, glossy leaves that are oval-shaped and around 5-10 cm long. The plant produces small, fragrant flowers that are dark purple or black in color and come in clusters. The plant also produces small, orange fruit that is not edible.
Uses
The Pittosporum tenuifolium Gaertn. plant is commonly used in landscaping as a hedge, border, or accent plant, due to its beautiful foliage and compact nature. It is also used in traditional medicine in New Zealand to treat a variety of ailments, including skin irritations and sore throats. The plant's wood is also used for making small tool handles and other small wooden objects.
Light Requirements
Pittosporum tenuifolium Gaertn. prefers full sun to partial shade. It can grow well in both shaded and exposed areas, but it requires at least six hours of sunlight per day to maintain healthy growth and avoid stunted growth.
Temperature Requirements
This plant can grow in a range of temperatures, but it prefers a mild coastal climate with moderate temperatures between 60-75°F (15-24°C). It can tolerate frost, but if the temperature drops below 20°F (-7°C), it can cause damage to the plant.
Soil Requirements
Pittosporum tenuifolium Gaertn. requires well-drained soil that is rich in organic matter. It can grow in various types of soils, such as sandy, clay, and loamy soils, as long as it is well-draining. The ideal soil pH for this plant is between 6.0-7.5. It can tolerate a slightly acidic to slightly alkaline soil.
Cultivation Methods
Pittosporum tenuifolium Gaertn. is a hardy plant that can grow in a wide range of soils, including loamy, sandy, and clay. It prefers well-drained soil rich in organic matter but can tolerate poor soil conditions. The plant grows well in areas that receive full sun or partial shade. Pittosporum tenuifolium Gaertn. requires regular watering to establish roots and grow properly.
The plant can be propagated from seeds or cuttings. Seeds should be sown in a well-draining, nutrient-rich soil mix, kept moist, and exposed to bright, indirect light. Cuttings should be taken during the growing season from a healthy and established plant. The cuttings should be kept moist and placed in a well-draining soil mix under bright, indirect light until they root.
Watering Needs
Pittosporum tenuifolium Gaertn. requires regular watering, especially during the growing season. The plant should be watered deeply, ensuring that the soil is moist but not waterlogged. Watering should be reduced in the winter to avoid waterlogging. Overwatering may lead to root rot and other diseases, while underwatering may cause the leaves to wilt and brown.
The frequency of watering depends on various factors, including the type of soil, temperature, and humidity. It is recommended to water Pittosporum tenuifolium Gaertn. when the top 2-3 inches of soil are dry. To help retain moisture, add a layer of organic mulch around the plant.
Fertilization
Fertilization is essential for the healthy growth of Pittosporum tenuifolium Gaertn. The plant requires regular feeding with a balanced fertilizer that contains equal parts of nitrogen, phosphorus, and potassium. Fertilization should be carried out during the growing season, from spring to early fall, at a rate of once every 4-6 weeks.
The amount of fertilizer required depends on the size and age of the plant. Younger plants require less fertilizer than older and established plants. Always follow the manufacturer's instructions when applying a fertilizer. Overfertilization may lead to damage or kill the plant, while underfertilization may result in stunted growth and yellowing leaves.
Pruning
Pittosporum tenuifolium Gaertn. requires occasional pruning to maintain its shape and promote healthy growth. The best time to prune the plant is during the dormant season, which is usually in winter. During this time, the plant is inactive, and pruning will not harm its growth.
The pruning should be done carefully to avoid damaging the plant. Always use sharp and sterile pruning tools to make clean cuts. Dead or diseased branches should be removed immediately, while crossing branches and those growing inward should be removed to improve air circulation and light penetration. The plant can also be pruned to maintain its shape and size, keeping in mind its natural growth habit.
Regular pruning not only keeps the plant healthy but also helps to increase its lifespan. It is recommended to remove no more than one-third of the plant during a single pruning season.
Propagation of Pittosporum tenuifolium Gaertn.
Pittosporum tenuifolium Gaertn. can be propagated through three methods: seeds, cuttings, and layering.
Propagation through Seeds
Seeds of Pittosporum tenuifolium Gaertn. require a period of cold stratification before sowing. The seeds collected in autumn or winter can be placed in a cold frame or a refrigerator where temperatures remain around 4-5°C for about two months. After this period, the seeds can be sown indoors, in trays filled with a mixture of compost and sand. The seeds should be covered with a thin layer of soil and kept in a warm and humid place. Germination usually takes about four weeks. Once the seedlings are large enough, they can be transplanted into individual pots and placed in a sunny location.
Propagation through Cuttings
Softwood cuttings of Pittosporum tenuifolium Gaertn. can be taken in the spring or summer. The cuttings should be about 10-15 cm long and should be taken from the current season's growth. The lower leaves of the cutting should be removed, and the stem should be dipped in rooting hormone powder. The cuttings should be inserted into a mixture of compost and sand, and the container should be covered with a plastic bag to retain moisture. The container should be kept in a shaded area with a temperature range of 18-21°C. The cuttings should root in about two to three months. Once the roots have formed, the cuttings can be transplanted into individual pots and placed in a sunny location.
Propagation through Layering
Pittosporum tenuifolium Gaertn. can also be propagated through layering. In this method, a low-hanging branch of the plant is selected, and a small portion of the bark is removed from where the branch touches the soil. The branch is then bent towards the soil, and the portion where the bark has been removed is covered with a mixture of compost and sand. The branch should be secured to the ground using pegs, and the container should be kept moist. Rooting should occur after a few months, and once the roots have formed, the new plant can be detached from the parent plant and transplanted into an individual pot.
Disease and Pest Management for Pittosporum tenuifolium Gaertn.
Pittosporum tenuifolium Gaertn. is a hardy plant that is commonly grown in gardens and landscapes. However, like any other plant, it is susceptible to various diseases and pests that can affect its growth and development. Here are some common diseases and pests that might affect Pittosporum tenuifolium Gaertn. and ways to manage them.
Common Diseases
1. Phytophthora root rot: This is a soil-borne disease that is caused by a fungus. It can cause the roots of the plant to rot and eventually lead to the death of the plant. To manage this disease, ensure proper drainage and avoid overwatering the plant. Also, avoid planting the plant in areas with poor drainage.
2. Leaf spot: This is a fungal disease that causes black or brown spots on the leaves of the plant. It can affect the overall health of the plant by reducing its ability to photosynthesize. To manage this disease, remove and dispose of the affected leaves. Ensure the plant is properly hydrated and fertilized to boost its immunity to the disease.
Common Pests
1. Scale insects: These are small, oval-shaped insects that attach themselves to the leaves and stems of the plant. They can cause yellowing of leaves and eventual leaf drop. To manage these pests, prune the affected parts of the plant and spray the unaffected areas with insecticidal soap.
2. Mealybugs: These are small, soft-bodied insects that can be found on the undersides of leaves and in leaf axils. They feed on the sap of the plant and can cause wilting and stunted growth. To manage these pests, remove and dispose of the affected parts of the plant and spray the unaffected areas with insecticidal soap.
By properly managing diseases and pests, you can help your Pittosporum tenuifolium Gaertn. plant thrive and prosper in your garden or landscape.
