|Other common names||scented grass, holy grass|
|Scientific name||Hierochloe redolens|
|Family||Poaceae (grass family)|
Kāretu is a large grass whose scented leaves, with the midrib removed, were traditionally used for plaiting into belts and headbands. Sitting and sleeping areas were strewn with leaves of kāretu. The flowering tops of kāretu and the roniu (Brachyscome radicata) were wrapped in fibrous leaves and worn as a scented necklace. Various scented oils were prepared that included kāretu. Moriori men would use kāretu as a love potion, placing a piece of leaf in a sleeping woman’s hair, or in a place that she would later sit or sleep on.
Kāretu is a large robust grass that forms loose tufts up to about 1 m tall, although much smaller on harsh sites.
Unfamiliar grasses can be difficult to identify unless close attention is paid to details of their foliage and flower parts. Some characteristics are rather complex to go into here, but useful diagnostic features of kāretu leaves are as follows:
The leaf blades, above the sheath, are up to 70 cm long, mostly flat apart from slightly inwardly rolled margins toward the base, and broad at 8−12 mm wide. They are dull green above and glossy green beneath. They are usually hairless and smooth above but the main veins are prominent and rough to touch on the lower surface, and the margins may be prickle-toothed.
The leaf sheath, the lower part of the leaf that tightly clings to the stem, is 15−30 cm long and often purplish on the lower portion.
An important diagnostic feature is the smell, reminiscent of coconut or fresh-mown hay. The green leaf has only a faint scent, but the odour becomes strong as the leaf dries.
As is common to most fast-growing plants on fertile surfaces, kāretu is palatable to grazers and browsers, but is intolerant of heavy browsing. Hence the wide introduction of wild and domestic herbivores (sheep, cattle, rabbits and hares, deer, possums, goats) and competition from browse-tolerant introduced grasses have seen a marked decline in the abundance of kāretu since the arrival of Europeans.
Division of mature plants is the usual method of propagation, but kāretu can also be grown from seed. Collect dry seed in January and February. Seed can be sown fresh or stored, but germination is enhanced following storage in a fridge for one month. Sow seeds on the surface of potting mix, or with a very thin covering. Sown seeds should be kept in a well-lit position out of direct sunlight, and held at 15−20°C. This plant is sometimes available at specialist nurseries.
Prepared by Sue Scheele and Peter Sweetapple