Pandanus julianettii

Pandanus julianettii, or karuka, is in the Pandanaceae family. It comes from New Guinea and grows in wet tropical regions. People grow it, tend wild stands, and gather its seeds. These seeds have long helped feed people in New Guinea. Its exact place among plant groups is still unclear. One source says it may be a group grown by people that came from another species.

This evergreen shrub or small tree grows fast. Garden guides give a height of about 13 feet [4 metres]. They give a spread of about 10 feet [3 metres]. A broader account says it can reach 66 feet [20 metres]. Young plants often have just one stem with no branches. Older plants form a few branches. Long leaves shaped like swords grow in groups at branch tips. Each leaf can reach about 10 feet [3 metres]. The leaves have prickles, so take care when handling them.

Karuka suits the damp air of tropical highlands. Records place it at heights of 4,900–9,500 feet [1,500–2,900 metres]. It grows best with a yearly mean temperature of 13–24°C. Sources say it can cope briefly with temperatures near 0°C. This does not prove it can withstand frost with any certainty. PFAF lists USDA zones 10–12. Plants grow in sun or light shade and favour forest clearings. They need moist soil that drains well and has plenty of humus. Light sandy soils and medium loams suit them. Detailed grow guides favour acid soil and prefer pH 4.5–5.5. The plant copes with strong winds, but not coastal exposure.

The oily seeds serve as food and contain protein. People also cook and eat the inner leaves. They sometimes cook the tips of aerial roots, which grow above ground. The plant yields fibre for making cloth. These uses give it value in food forests and crop plantings. The supplied evidence does not describe the flowers or say when they bloom. It gives no detailed account of the fruit either. Sources report no known hazards, but do not prove pet safety. The leaf prickles still pose a clear risk when handling plants.

Growers use seeds, cuttings from branch tips, and shoots near ground level. Guidance says to soak seeds for 24 hours before sowing. Plants grown from cuttings start to yield after five to eight years. Plants grown from seed take longer and form taller, straighter trunks. PFAF reports no known use as medicine and no risk of becoming a weed. The supplied sources name no specific pests or diseases.