New Zealand Iceplant
Disphyma australe
Disphyma australe , commonly known as New Zealand Iceplant or Native Iceplant, is a succulent perennial groundcover endemic to the coastal areas of New Zealand. This hardy and resilient plant is highly valued for its ability to thrive in harsh, exposed conditions, such as rocky shores, cliffs, and sand dunes, where few other plants can survive. Its fleshy leaves and vibrant, often pink or white, daisy-like flowers make it an attractive and ecologically important species for coastal stabilization and xeriscaping.
Plant Description
Disphyma australe is a prostrate, sprawling succulent perennial that forms dense mats or cushions, typically growing only a few centimeters high but spreading widely. Its leaves are fleshy, triquetrous (three-sided) or cylindrical, bright green, and covered in bladder-like cells that give them a glistening, "icy" appearance. From spring to autumn (and often year-round in mild climates), the plant produces numerous showy, daisy-like flowers, typically 2-4 cm in diameter. These flowers can range in colour from bright pink to magenta, or white, with many slender petals. The flowers open in the sun and close at night or on cloudy days.
Quick Facts
| Scientific Name | Disphyma australe |
|---|---|
| Family | Aizoaceae (Iceplant family) |
| Form | Prostrate succulent perennial groundcover |
| Light | Full sun |
| Soil | Well-drained, sandy, rocky, tolerant of poor soils |
| Water | Low, highly drought-tolerant |
| Water Needs | Low |
| Frost Tolerance | Half Hardy |
| Salt Tolerance | High |
| Height | 2-10 cm |
| Spread | Spreading mats up to 1 m or more |
| Flowering Season | Spring to autumn (often year-round) |
| Flower Colour | Pink, magenta, or white |
| Foliage | Evergreen, fleshy, triquetrous, bright green leaves |
| Growth Rate | Moderate to fast |
| Lifespan | Perennial |
| Unique Features | Succulent, salt-tolerant, excellent coastal groundcover. |
Climate Best Suited to
Disphyma australe is perfectly adapted to coastal conditions, tolerating salt spray, strong winds, and periodic drought. This succulent thrives in areas with mild winters (minimum -2°C) and warm summers, preferring full sun and excellent drainage. It performs best in coastal regions with 600-1200mm annual rainfall.
Regional Suitability
| City | Climate Suitability |
|---|---|
| Whangārei | Ideal |
| Auckland | Ideal |
| Hamilton | Suitable |
| Tauranga | Ideal |
| Rotorua | Marginal |
| Gisborne | Ideal |
| New Plymouth | Ideal |
| Napier | Ideal |
| Whanganui | Ideal |
| Palmerston North | Suitable |
| Wellington | Ideal |
| Nelson | Ideal |
| Christchurch | Suitable |
| Dunedin | Suitable |
| Invercargill | Marginal |
Habitat
Natural Distribution
Disphyma australe is common on rocky coasts, cliffs, shingle beaches, and sand dunes throughout New Zealand. It is a key colonizer of exposed, infertile sites, where its extensive root system and mat-forming habit help to stabilize loose substrates. It is often found growing alongside other hardy coastal plants, playing a vital role in preventing erosion.
Conservation Status
Current Threats and Protection
Disphyma australe is classified as "Not Threatened" under the New Zealand Threat Classification System. It is a widespread and common species in its preferred coastal habitats. Its resilience and ability to colonize disturbed areas contribute to its stable population status. However, like all coastal species, it can be vulnerable to habitat destruction from coastal development and competition from invasive exotic iceplant species.
How to Grow
Cultivation Requirements
Disphyma australe is an extremely low-maintenance plant, ideal for challenging garden spots. It absolutely requires full sun and extremely well-drained soil; it tolerates sandy, rocky, or gravelly substrates with very low fertility. Overwatering is its main enemy, leading to root rot. Once established, it is highly drought-tolerant and requires virtually no supplementary watering, making it perfect for xeriscaping. Protection from severe frosts is beneficial, particularly for young plants or in inland areas.
Planting Guide
Best Planting Practices
Plant Disphyma australe in full sun in spring or early summer in a location with excellent drainage, such as a rock garden, coastal bank, or container. Prepare the planting site by incorporating coarse sand or grit to ensure sharp drainage. Dig a shallow hole, just deep enough to accommodate the root ball. Plant at the same level as its nursery container, firm the soil gently, and water lightly once. After establishment (a few weeks), reduce watering significantly. Space plants about 30-50 cm apart for groundcover, as they will spread to fill the area.
Ecological Role
Environmental Benefits
Disphyma australe plays a crucial ecological role in stabilizing vulnerable coastal ecosystems. Its dense, mat-forming growth helps to bind loose sand and soil on dunes and cliffs, preventing erosion from wind and water. Its abundant, nectar-rich flowers provide a valuable food source for native insects, including bees and butterflies, contributing to coastal biodiversity. It also creates microhabitats for small invertebrates within its dense foliage.
Uses
Traditional and Modern Applications
Disphyma australe is an excellent choice for coastal gardens, rock gardens, green roofs, and xeriscaping where its drought and salt tolerance are highly advantageous. Its aesthetic appeal makes it suitable for groundcover, erosion control, and as a filler plant in sunny, dry areas.
Landscaping Uses
Garden Design Applications
This New Zealand iceplant is superb for challenging coastal sites where a robust, fast-spreading groundcover is needed. It is ideal for stabilizing banks, slopes, and sand dunes. It works well in rockeries, cascading over walls, or as an informal lawn substitute in low-traffic, dry areas. Its vibrant flowers provide a splash of colour, especially effective when mass-planted.
Seasonal Care
Year-Round Maintenance
Disphyma australe is a low-care plant. Ensure excellent drainage year-round. In spring, a light trim can tidy up any untidy growth and encourage denser foliage. Water sparingly, if at all, during dry spells once established. Protect from severe frosts if grown in marginal climates.
Pruning
Pruning Techniques
Pruning Disphyma australe is minimal and generally only required to contain its spread or to remove any dead or straggly sections. A light trim can be given after the main flowering period to encourage bushier growth and maintain a tidy appearance. Use clean, sharp shears.
How to Grow New Zealand Iceplant
From Cuttings
Disphyma australe is remarkably easy to propagate from cuttings, making it simple to establish new plants or expand existing mats. Simply break off or cut a healthy stem segment, approximately 10-15 cm long, from an established plant. Remove the lower few leaves to expose a clean stem. Allow the cutting to callus for a day or two in a dry, shaded spot before planting (though it often roots successfully without this step). Insert the cuttings directly into well-drained, sandy soil or a propagation mix. Keep the soil lightly moist (but never waterlogged) until roots form, which typically occurs within a few weeks. Cuttings can be taken at any time of year in mild climates, but spring and summer are ideal.
From Seed
Propagation from seed is also possible but generally slower and less common than propagation by cuttings. Collect seeds from the dried flower heads once they are mature, typically in late summer to autumn. Sow the tiny seeds thinly onto a well-draining seed-raising mix, pressing them lightly onto the surface without covering, as they may require light for germination. Maintain consistent moisture and provide warm temperatures (around 18-24°C or 65-75°F) in a bright location. Germination can be variable and may take several weeks. Once seedlings are robust enough to handle, prick them out into individual pots and grow them on in a bright, airy location until strong enough for planting out.
General Cultivation
New Zealand Iceplant (Disphyma australe) is an extremely low-maintenance succulent perennial groundcover, ideally suited for challenging coastal and dry garden spots. It absolutely requires full sun and extremely well-drained soil, tolerating sandy, rocky, or gravelly substrates with very low fertility. Overwatering is its main enemy, leading to root rot; allow the soil to dry out completely between waterings. Once established, it is highly drought-tolerant and requires virtually no supplementary watering, making it perfect for xeriscaping. It is highly tolerant of salt spray and strong winds. Protection from severe frosts is beneficial, particularly for young plants or in inland areas. Plant in full sun in spring or early summer, ensuring excellent drainage. Space plants approximately 30-50 cm apart for groundcover, as they will spread readily. Minimal pruning is typically required, mainly for shaping or removing any dead or straggly sections to maintain tidiness.
Pests and Diseases
Common Problems and Solutions
Disphyma australe is generally a very robust plant, largely free from serious pests and diseases. The primary issue to avoid is root rot, which occurs in poorly drained or excessively wet soils. Ensure sharp drainage and avoid overwatering. Occasionally, mealybugs or aphids might appear on new growth, but these are usually manageable with horticultural soap.
Cultural Significance
Traditional Uses and Values
As a resilient endemic species of New Zealand's coastlines, Disphyma australe contributes to the country's unique biodiversity. Its ability to thrive in harsh environments symbolizes adaptation and strength in the face of adversity. While specific traditional Māori uses may not be widely documented, its presence as a colonizer of coastal areas would have made it a familiar plant to coastal iwi (tribes).
Bonus Tip
Expert Growing Advice
Disphyma australe is an excellent choice for green roofs or vertical gardens in coastal or dry climates due to its shallow root system, drought tolerance, and ability to withstand extreme exposure. Its vibrant flowers will attract pollinators even in these challenging urban environments.
