Snow Grass
Chionochloa australis
grasses -description">Full sun, low fertility and sharp drainage; drought‑tolerant once established; cut back dead thatch in late winter.
Description
Chionochloa australis is a species of tussock grass endemic to the South Island of New Zealand. It forms dense, upright tussocks, typically growing to about 1 meter in height and similar width. Its leaves are stiff, wiry, and a striking pale yellowish-green or glaucous-green colour, often with reddish or purplish tints at the base, especially in exposed conditions. The flower stalks are slender and bear small, purplish-brown flower heads in summer. This slow-growing tussock is a distinctive feature of subalpine and alpine landscapes, particularly on exposed, windswept ridges and slopes, and in areas with poor, rocky soils.
Quick Facts
Chionochloa australis is a hardy, upright tussock grass valued for its distinctive form and adaptability to harsh alpine conditions. It is a long-lived perennial with a slow to moderate growth rate, reaching up to 1 meter in height and similar spread.
| Scientific Name | Chionochloa australis |
|---|---|
| Height | Up to 1 m |
| Spread | Up to 1 m |
| Water Needs | Low to moderate; free-draining soils |
| Light | Full sun |
| Frost Tolerance | High - tolerant of severe freezes |
| Salt Tolerance | Low to moderate |
| Growth Rate | Slow to moderate |
| Lifespan | Long-lived perennial |
| Soil | Lean, gritty, free-draining |
Climate Suitability
Chionochloa australis is highly adapted to the harsh conditions of subalpine and alpine environments, experiencing cold winters with snow and cool, dry summers. It is exceptionally frost-hardy and thrives in areas with good air circulation and low humidity. While it tolerates a range of New Zealand climates, it performs best in cooler regions and requires careful siting in warmer, more humid areas to avoid stress and disease.
| City | Climate Suitability |
|---|---|
| Whangārei | Suitable |
| Auckland | Suitable |
| Hamilton | Suitable |
| Tauranga | Suitable |
| Rotorua | Suitable |
| Gisborne | Suitable |
| New Plymouth | Suitable |
| Napier | Suitable |
| Whanganui | Suitable |
| Palmerston North | Suitable |
| Wellington | Suitable |
| Nelson | Suitable |
| Christchurch | Suitable |
| Dunedin | Suitable |
| Invercargill | Suitable |
Habitat
Natural Distribution
occurs in natural habitats characteristic of Aotearoa, forming part of distinctive plant communities where site stress and local disturbance shape vegetation patterns. It favours exposed slopes, screes or fellfields with thin, rapidly drained mineral soils, enduring intense radiation, wind and freeze-thaw cycles. On the coast it occupies sunny, wind‑prone sites with sandy or rocky substrates, where salt‑laden air and periodic drought limit competition. These preferences explain its patchy distribution and sensitivity to changes in hydrology, competition and disturbance regimes. Chionochloa australis
Conservation Status
Current Threats and Protection
are influenced by land use, browsing and weeds. Protecting intact habitat mosaics, reducing browser pressure, and managing invasive plants sustain recruitment. Where local stands are small or isolated, eco‑sourced augmentation and careful site stewardship help secure long‑term viability. Chionochloa australis Populations of
How to Grow
Cultivation Requirements
Provide free‑draining soils and high light appropriate to the species’ natural range. Use gritty, stony mixes and an open aspect with moving air; keep crowns high and dry, especially in winter. Choose warm, sunny sites with shelter from the fiercest onshore winds; avoid heavy, waterlogged soils.
Planting Guide
Best Planting Practices
Plant in the cool, moist months into weed‑free ground. Set plants slightly proud of the surrounding soil, water to settle, and mulch with coarse gravel or woodchips while keeping the stem base clear. Grouping two to three plants replicates natural patterns and improves establishment under local conditions.
Ecological Role
Environmental Benefits
contributes structure and seasonal resources where it grows, providing cover and habitat for invertebrates and, when flowering or fruiting, nectar, pollen or seed for fauna. By tolerating the stresses of its environment, it helps stabilise sites and enrich small‑scale habitat diversity. Chionochloa australis
Uses
Traditional and Modern Applications
Ideal for rock and gravel gardens that emulate alpine processes, or for specialised collections. Suited to sunny, maritime gardens with sandy or rocky soils where wind and salt are considerations.
Landscaping Uses
Garden Design Applications
Excellent for rock gardens, alpine collections, and naturalistic plantings. Best used in open, well-drained positions where its distinctive form can be appreciated. Combines well with other native alpine plants and provides year-round structure. Consider placement carefully due to sharp foliage - avoid high-traffic areas. Creates dramatic focal points in contemporary and native-themed garden designs.
Seasonal Care
Year-Round Maintenance
Spring management focuses on removing winter-damaged foliage and assessing drainage. Summer care emphasizes maintaining adequate moisture without waterlogging. Autumn preparation includes reducing irrigation and ensuring good air circulation. Winter protection may require covering in areas subject to excessive moisture. Year-round monitoring ensures early detection of problems and maintenance of optimal growing conditions.
Pruning
Pruning Techniques
Little pruning is required; remove dead or crossing material after flowering and avoid hard renovation cuts. Light tip‑pruning maintains compact form without compromising the plant’s natural character.
How to Grow Snow Grass
From Seed
Propagation of Chionochloa australis from fresh seed is the most common method. Collect seeds from the dried flower heads once they are mature, typically in late summer to autumn. Sow the fresh seeds onto a very free-draining, gritty seed-raising mix, lightly covering them with fine grit or sand. A period of cold stratification (4-8 weeks in a refrigerator) can enhance germination, mimicking natural winter conditions. Maintain cool, airy conditions and consistent moisture (avoiding waterlogging) in a protected environment. Germination can be erratic and slow, often taking several weeks to months. Once seedlings are robust enough to handle, prick them out into individual pots and grow them on in a cool, bright, and well-ventilated location until strong enough for planting out.
From Division
Division of established tussocks is a viable method for propagating Chionochloa australis, especially for larger, mature clumps. This is best performed in early spring as new growth commences, or in autumn. Carefully lift the entire tussock and, using a sharp spade or knife, divide it into smaller sections, ensuring each division has healthy roots and several growth points. Replant divisions immediately into well-drained, gritty soil at the same depth as the original plant. Water thoroughly after replanting and keep consistently moist until established. Division helps to rejuvenate older plants and is an effective way to maintain genetic purity.
General Cultivation
Snow Grass (Chionochloa australis) is a hardy tussock grass that thrives in open, sunny sites with sharp drainage and low fertility, mimicking its natural subalpine and alpine habitat. It requires full sun, good air circulation, and lean, gritty soils (e.g., a mix with pumice, coarse sand, or gravel) to prevent root rot, particularly in winter. Avoid rich organic soils or heavy, waterlogged conditions. It is exceptionally drought-tolerant once established and highly resistant to severe freezes. Provide gritty, stony mixes and an open aspect with moving air; keep crowns high and dry, especially in winter. Choose warm, sunny sites with shelter from the fiercest onshore winds. Water requirements are low to moderate once established, but occasional deep watering during prolonged dry spells can be beneficial. Minimal pruning is required; old, dead thatch can be cut back in late winter to encourage fresh growth, but often a light tidying is sufficient to maintain its attractive form.
Pests and Diseases
Common Problems and Solutions
Good siting prevents most problems-sharp drainage and appropriate exposure are key. Crown and root rots arise if winter wet persists; keep crowns elevated and water moving. Protect young plants from browsing where deer, goats or rabbits are present.
Cultural Significance
Chionochloa australis holds cultural significance as a distinctive alpine tussock grass, embodying the resilience and unique beauty of New Zealand's high-country flora. While specific traditional Māori uses may not be widely documented for this particular species, tussock grasses in general played roles in shelter, bedding, and as indicators of ecological health within alpine landscapes.
Bonus Tip
Expert Growing Advice
For best results with Chionochloa australis, plant in full sun with sharp drainage and low fertility, mimicking its natural alpine environment. Avoid rich soils or excessive water, as these can lead to lush but weak growth. Cut back dead thatch in late winter to encourage fresh, vibrant foliage.
