Pittosporum tenuifolium Irish Luck - Kohuhu

Pittosporum tenuifolium Irish Luck is a medium to large variety of Pittosporum with small leaves. This fast-growing bush features ornamental shiny green foliage and very dense vegetation. It is tolerant of pruning making it the ideal plant for hedges or topiaries to effectively replace box. It is resistant to pests and in late spring, it offers a discreet flowering that releases a honey scent in the evening. Thriving in full sun, or possibly in partial shade in the south, it tolerates summer drought and limestone soils well. More hardy than variegated varieties, it withstands cold temperatures down to approximately -12°C once well established.

Pittosporum is practically the only genus known in our regions of the Pittosporaceae family, and the richest in species, approximately 150, mainly shrubs and trees, with a good number originating from New Caledonia and New Zealand. Alongside its cousin, Pittosporum tobira, P. tenuifolium is certainly the most common in our gardens in mild climates. It is native to New Zealand, where it is common in coastal and mountain forests up to 900 m, flowering in October-November. In its native country, it forms a highly branched shrub 3 to 6 m tall, or a small evergreen tree with a slender trunk 9 to 10 m tall, resistant to frost down to -10°C but vulnerable to icy winds. Its common name locally is Kōhūhū, or Black Matipo.
The species has given rise to several horticultural varieties with highly decorative foliage, often variegated or purple. Irish Luck 'PTG18' is a cultivar selected by New Zealand breeders John and Kathleen Richie in Ōtāne, a locality on the east coast of the North Island (250 km north of the capital, Wellington). This variety is distinguished by an upright habit with rapid growth and reaches a height of 3 m with a spread of 2 m ten years after planting. Hardier than variegated or colourful varieties, it withstands temperatures down to -10/-12°C once well rooted in the soil. It has dense, bushy vegetation with very branched dark twigs. These bear alternate, ovate leaves on short petioles. Shiny mid-green with small hairs on their edges, they measure 4 to 4.5 cm long by 2.5 cm wide. Their colour provides a nice contrast against the dark purple tips of the twigs. Flowering occurs in late spring or early summer. Small dark purple flowers appear in the leaf axils and release a pleasant scent in the evening. They then develop into round fruits, initially green and almost black when ripe.

Highly tolerant of pruning, this Pittosporum is perfect for hedges or topiaries. Thriving in full sun and tolerating partial shade, especially in southern areas, it requires well-drained soil, a warm location, and protection from prevailing winds. Used in hedges, it will enhance the plants at its feet. Pair it with the compact Physocarpus opulifolius Magic Ball, whose foliage changes from spring orange to golden yellow, before igniting in red in autumn, for a stunning scene throughout the growing season. Somewhat taller but tolerating severe pruning, Cotinus coggygria Old Fashioned will create the same botanical magic with its oval leaves emerging in orange-purple, then turning blue-green before ending in a burst of warm colours, blending bright pink, red, and orange. Equally cold-resistant, if not more so, Grevillea junipera with dark green needle-like foliage will delight you with its striking and long-lasting bright red flowering, particularly aesthetic.