Lepidium oleraceum Explore more in the native plants index.
Cook's Scurvy Grass (Lepidium oleraceum) is a native species valued in gardens and restoration for its form and resilience in suitable conditions. Learn more in our native plants guide.
Cook’s Scurvy Grass (Lepidium oleraceum) is a historically significant and critically endangered native New Zealand coastal cress. It is a leafy, upright, and branching herb that can grow up to 1 meter tall. Its fleshy, glossy green leaves are packed with Vitamin C, which is why it was famously used by Captain Cook and his crew to successfully combat scurvy during their voyages. This fast-growing biennial or short-lived perennial produces small white flowers in dense racemes. Once widespread on coastal cliffs, scree, and beaches, particularly in areas enriched by seabird and seal colonies, it is now one of New Zealand's most threatened plants, facing extinction due to habitat loss, pests, and diseases.
| Scientific Name | Lepidium oleraceum |
|---|---|
| Common Name | Cook’s Scurvy Grass, Nau |
| Family | Brassicaceae |
| Height | Up to 1 m |
| Spread | Up to 1 m |
| Flowers | White, mainly from September to March |
| Water Needs | Moderate, well-drained coastal soil |
| Light | Full sun to partial shade |
| Habitat | Coastal areas with fertile, well-drained soil |
| Conservation Status | Threatened – Nationally Critical |
| Frost Tolerance | Moderate; protect from hard frosts |
| Salt Tolerance | Very high; naturally adapted to coastal conditions |
| Growth Rate | Moderate |
| Lifespan | Perennial |
Cook’s Scurvy Grass (Lepidium oleraceum) is naturally found in coastal environments throughout New Zealand. It thrives in temperate maritime climates with moderate temperatures, high humidity, and protection from extreme weather. The species prefers areas with consistent moisture but excellent drainage, and benefits from the mild temperatures and salt-laden air typical of coastal environments.
| City | Climate Suitability |
|---|---|
| Whangārei | Ideal |
| Auckland | Ideal |
| Hamilton | Ideal |
| Tauranga | Ideal |
| Rotorua | Ideal |
| Gisborne | Ideal |
| New Plymouth | Ideal |
| Napier | Ideal |
| Whanganui | Ideal |
| Palmerston North | Ideal |
| Wellington | Ideal |
| Nelson | Ideal |
| Christchurch | Ideal |
| Dunedin | Ideal |
| Invercargill | Ideal |
This plant demands highly fertile, well-drained soil. It naturally thrives in sites enriched by seabird guano, so it requires a soil rich in nutrients, particularly nitrogen. Amending the soil with well-rotted compost or chicken manure can help replicate these conditions. It will not tolerate waterlogged soil.
Full sun is essential for healthy growth. Cook’s Scurvy Grass should receive at least six hours of direct sunlight each day. A bright, open position will also help to reduce the risk of fungal diseases.
Keep the soil consistently moist, but not saturated, especially during the establishment phase and in dry summer months. Good drainage is critical to prevent root rot. It is also reported to benefit from an occasional spray of salt water, which mimics its coastal environment.
Cook’s Scurvy Grass holds immense historical significance as the plant that helped prevent scurvy among Captain Cook's crew during their Pacific voyages. The Māori name 'Nau' reflects its traditional use as a vegetable by indigenous peoples, highlighting its cultural value long before European contact.
This is the main growth period for Cook’s Scurvy Grass. Sow fresh seeds and monitor young plants carefully for pests like aphids and slugs. Ensure consistent moisture and apply a liquid fertilizer to support vigorous growth.
Flowering is most prolific during summer months. Water regularly during dry spells and maintain vigilant pest monitoring, especially for cabbage white butterflies and signs of white rust disease.
As growth slows, reduce watering frequency. This is an excellent time to collect ripe seeds for the following year's sowing. Remove any plants that are dying back to maintain garden hygiene.
As this plant is often treated as an annual, most will have completed their life cycle. Protect any overwintering plants from severe frost and keep the area clean to reduce pest and disease carryover.
Cook’s Scurvy Grass (Lepidium oleraceum) requires minimal pruning as it is typically grown as an annual or biennial. Management focuses on maintaining plant health and collecting seeds for conservation.
Always use clean, sterilized tools when working with this critically endangered species to prevent disease spread. Handle plants gently as they can be quite delicate.
The ideal time to plant Cook’s Scurvy Grass (Lepidium oleraceum) is during spring after the last frost, or in early autumn. These seasons provide mild temperatures and reliable moisture needed for successful establishment. As it is often grown as an annual or biennial, timing is crucial for success.
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Monitor newly planted specimens closely for the first few weeks. Maintain consistent moisture without waterlogging, and watch for early signs of pest or disease issues. This critically endangered species requires exceptional care during establishment.
Cook’s Scurvy Grass is a nationally critical and historically significant native New Zealand coastal cress. Its fleshy, glossy green leaves, packed with Vitamin C, were famously used by Captain Cook to combat scurvy. This fast-growing biennial or short-lived perennial is now one of New Zealand's most threatened plants, making its cultivation primarily a conservation effort. It thrives in coastal environments with highly fertile, well-drained soil and full sun. Understanding its propagation methods is crucial for maintaining genetic diversity and supporting its survival.
Propagating Cook’s Scurvy Grass from fresh seed is essential for maintaining genetic diversity and supporting conservation efforts. Collect fresh, ripe seeds from healthy parent plants. Sow seeds immediately in a well-draining seed-raising mix, lightly covering them with fine sand or vermiculite. Maintain consistent moisture (but not waterlogged) and temperatures between 15-20°C for optimal germination. Germination typically occurs within 2-3 weeks. Transplant seedlings when large enough to handle, taking extreme care due to their delicate nature. Due to its critical status, seeds are often sourced from specialized conservation nurseries.
Semi-hardwood cuttings can be taken as an alternative propagation method, though seed propagation is generally preferred for conservation purposes to maintain genetic diversity. Take semi-hardwood cuttings from healthy parent plants. Remove lower leaves and dip in rooting hormone. Insert into a well-draining propagation mix. Maintain high humidity and consistent moisture. Rooting typically occurs within 3-4 weeks. This method can be useful for rapidly increasing stock of specific genotypes for reintroduction programs, but should be done under expert guidance due to the plant's endangered status.
Cook’s Scurvy Grass (Lepidium oleraceum) is highly susceptible to a range of pests and diseases, which is one of the factors contributing to its critical conservation status. Constant vigilance is required when cultivating this endangered species.
Due to its critical conservation status, any pest or disease management should prioritize organic and non-harmful methods. Consult with conservation specialists when dealing with issues in cultivated specimens.
When growing Cook’s Scurvy Grass, consider creating a 'historical garden' section that tells the story of its importance to both Māori and European explorers. This adds educational value and highlights the critical conservation importance of this remarkable plant that once helped save lives at sea.
Explore other native plants that share similar coastal characteristics with Cook’s Scurvy Grass (Lepidium oleraceum), offering insights into New Zealand's specialized coastal flora and conservation needs.
Understanding the natural habitat of Cook’s Scurvy Grass (Lepidium oleraceum) is crucial for its conservation and any cultivation attempts. This species has very specific habitat requirements.
The ecological relationships of Cook’s Scurvy Grass (Lepidium oleraceum) are closely tied to coastal environments and seabird colonies, making it one of New Zealand's most specialized native plants.
Cook’s Scurvy Grass (Lepidium oleraceum) is the focus of intensive conservation efforts due to its critically endangered status. Understanding these efforts is essential for anyone interested in this species.
Growing Cook’s Scurvy Grass (Lepidium oleraceum) requires adherence to strict conservation protocols and specialized horticultural techniques to support this critically endangered species.
Cook’s Scurvy Grass (Lepidium oleraceum) has very limited landscaping applications due to its critical conservation status. Any cultivation should be primarily for conservation and educational purposes.
The ecological importance of Cook’s Scurvy Grass (Lepidium oleraceum) within its native coastal ecosystem cannot be overstated. As a critically endangered species, its loss would represent a significant gap in New Zealand's biodiversity.
