Botanical name:

Lepidium oleraceum

Common name(s):

Nau, Cook's scurvy grass

About:

This plant is particularly famous because the renowned explorer James Cook had it gathered and provided it to his crew in an effort to prevent scurvy, which is a disease caused by a deficiency in Vitamin C. Once commonly found in coastal areas throughout New Zealand, it is now classified as a threatened species, with populations that are currently found only on some offshore islands and select sites throughout the South Island. The plant is characterised by its fleshy, sprawling appearance, featuring oval serrated leaves and producing small, delicate clusters of white flowers during the summer months. To maintain a healthy and attractive habit, regular pruning is recommended. It thrives best in a light soil, particularly when situated in a sunny location.

Natural habitat:

Now strictly coastal, L. oleraceum is usually found in friable well manured soils, guano deposits, or rock crevices associated with seabird roosts and nesting sites. Occasionally it grows under taller vegetation, and then usually near petrel or shear water burrows. The species is now mainly found on rock stacks, islets, and winds-horn headlands on rodent free offshore islands. In some places it has been found growing on sand or gravel beaches, and in one location it grows on boulders and clay that are part of an artificial sea wall. Historically this species was also known from the upper Waitaki Valley, well inland from the sea. This suggests that before human occupation it was once more widespread away from coastal situations.

Growing environment:

Frost, Sun, Salt, Wind, Coastal & Free draining tolerant.

Endemic distribution:

New Zealand’s Kermadec Island group, Three Kings Island group, North, South, Stewart Islands and the Bounty Islands group.

Height: 1m

Flowering: 

Flowers appear year-round, but mainly from September to March, with a white - yellow  coloured flower/s

Fruiting:

Fruiting occurs from December to April. Seed production is rapid so flowers, immature and ripe seed capsules are often found on the same plant.

Uses:

Bird food / Attractant, Bee food, Riparian plantings & Pioneer Plantings

How to grow:

Easy from fresh seed. Can be grown from semi-hardwood cuttings. Fast growing. Does best in friable soils enriched with N, P, K, in full sun. This species, and indeed all other representatives of the genus in New Zealand are very prone to fungal diseases and insect attack, and can be difficult to maintain. L. oleraceum is best treated as an annual.

** Seed germinates without pre treatment. Sow seed direct & keep moist until germination is complete.