Pittosporum tenuifolium Care Guide: How to Grow and Maintain them in NZ

Pittosporum tenuifolium In NZ

Pittosporum tenuifolium, commonly known as Kohuhu or Black Matipo, is a native New Zealand plant. It is characterized by its wavy, glossy leaves and small, dark-purple flowers that emit a pleasant scent, particularly in the evening. The plant can grow up to 10 metres tall, although it is often kept smaller through regular pruning.

Caring for Pittosporum tenuifolium

There are a few simple care tips that can make the world of difference to your trees:

Watering

• Regular watering is crucial, especially during the first year after planting. After planting do not let the tree dry out. The root ball needs to be constantly moist but not waterlogged. During dry spells, increase watering frequency, but be careful not to over-water, as Pittosporum tenuifolium can succumb to root rot caused by over-watering.

Pruning

• Pruning is an essential part of Pittosporum care to maintain its shape and encourage bushy growth. The best time to prune is in late winter or early spring, just before new growth begins. Remove any dead or diseased branches and shape the plant to your desired form.

Fertilizing

• Feed your Pittosporum tenuifolium with native tree fertiliser in spring. This provides the necessary nutrients for healthy growth.

Growing Pittosporum tenuifolium

Before you start planting, it's important to understand the ideal growing conditions for Pittosporum tenuifolium. This plant thrives in well-drained soil and can tolerate a range of soil types, from sandy to clay. It prefers a sunny to partially shaded location and is quite hardy, being able to withstand temperatures down to -10°C.

Planting Pittosporum tenuifolium

• The best time to plant Pittosporum tenuifolium is during the cooler months, from autumn to early spring. This allows the plant to establish its roots before the hot summer months. Choose a location in your garden that receives plenty of sunlight but also offers some protection from strong winds.
• Ensure the soil is well-drained. You can improve drainage by adding organic matter such as compost or well-rotted manure.
• The hole should be twice as wide and as deep as the root ball of your plant.
• Gently remove the plant from its container and place it in the hole. Make sure the top of the root ball is level with the surrounding soil.
• Fill the hole with soil, pressing down gently to eliminate air pockets.
• Give the plant a good soaking to help settle the soil around the roots.
• The Plant Company recommends the trees are staked for additional support.

Pest and Disease Management

Pittosporum tenuifolium is relatively pest-resistant, but it can occasionally be affected by pests such as aphids, scale insects, and caterpillars. Regularly inspect your plants for signs of infestation and treat them promptly with an insecticide or neem oil.

Good air circulation and proper watering practices can help prevent common diseases such as root rot and leaf spot. Avoid overhead watering to reduce the risk of fungal infections, and ensure plants are not overcrowded.

Propagation Techniques

Pittosporum tenuifolium can be propagated from cuttings or seeds.

Propagating from Cuttings

• Choose a semi-hardwood cutting, about 10-15 cm long, from a healthy plant.
• Remove the lower leaves and dip the cut end in rooting hormone.
• Place the cutting in a pot filled with a well-draining potting mix. Keep the soil moist and place the pot in a warm, bright location.
• Cuttings can take 8-12 weeks to root.

Propagating from Seeds

• Harvest seeds from mature Pittosporum fruit.
• Sow seeds in a seed tray filled with seed-raising mix. Lightly cover the seeds with soil and keep the tray in a warm spot.
• Ensure the seed mix remains moist but not waterlogged until germination occurs.
• Germination can take 12 weeks, depending on the variety, seed quality, and germination environment.