Marram in New Zealand: The Ultimate Guide to Coastal Management and Ecosystem Restoration

This comprehensive guide explores the complex role of Marram grass (Ammophila arenaria) within the New Zealand coastal landscape, detailing its historical introduction for dune stabilization and its subsequent transition into an invasive species that challenges indigenous biodiversity. We delve into the botanical mechanics of how Marram traps sand to create steep, unstable foredunes, comparing these structures with the gentle, rolling profiles formed by native Spinifex and Pingao. The article provides actionable insights for coastal property owners and community groups on identifying Marram, implementing removal strategies using chemical and mechanical methods, and navigating the ecological "best practices" for restoring native dune succession. From understanding the economic impact on coastal infrastructure to examining the long-term success of restoration projects in regions like the Manawatu and Canterbury, this resource serves as the definitive manual for managing Marram in Aotearoa.

The Historical Introduction of Marram to Aotearoa

Marram grass was intentionally introduced to New Zealand in the late 19th century as a tool for "reclaiming" vast areas of shifting coastal sands that threatened farmland and infrastructure. At the time, the European approach to coastal management favored the aggressive sand-binding capabilities of Ammophila arenaria, which was seen as superior to the less dense native vegetation. Government-led planting programs throughout the early 20th century successfully stabilized thousands of hectares of dunes, but this came at the cost of fundamentally altering the natural geomorphology of the New Zealand coastline. What was once a dynamic system of mobile "blowouts" and diverse plant communities became a monoculture of Marram-stabilized ridges that disrupted the natural flow of sand from the beach to the back-dunes.

• 1870s Introduction: Initial plantings aimed at protecting coastal settlements from migrating sand drifts.
• Government Mandates: Historical laws encouraged the planting of Marram to turn "unproductive" dunes into grazing land.
• Rapid Colonisation: Due to its hardy nature, Marram spread far beyond its original planting sites via seed and rhizome fragments.
• Displacement of Natives: Marram's dense growth habit outcompeted native species like Pingao and Spinifex.

1870s Introduction: Initial plantings aimed at protecting coastal settlements from migrating sand drifts.

Government Mandates: Historical laws encouraged the planting of Marram to turn "unproductive" dunes into grazing land.

Rapid Colonisation: Due to its hardy nature, Marram spread far beyond its original planting sites via seed and rhizome fragments.

Displacement of Natives: Marram's dense growth habit outcompeted native species like Pingao and Spinifex.

Spinifex / Pingao

Marram Grass

Low, wide, and rolling

Steep, narrow, and high

Dynamic and inland-flowing

Trapped at the foredune

High (native insects/birds)

Low (monoculture)

Botanical Characteristics and Identification of Marram

Identifying Marram grass is the first step for any coastal restoration project in New Zealand, as it often looks similar to native grasses to the untrained eye. Marram is a perennial, rhizomatous grass that grows in dense, upright tufts reaching up to 1.2 meters in height. Its leaves are tightly rolled, grey-green, and sharp-pointed, which helps the plant conserve moisture in harsh, salty environments. The most distinguishing feature is the flower head—a dense, spike-like panicle that appears in summer, carrying thousands of wind-dispersed seeds. Unlike native Spinifex, which has "tumbleweed" style seed heads that roll along the beach, Marram seeds are lightweight and travel high in the air, allowing the species to jump across coastal bays.

Distinguishing Marram from Native Spinifex

A key identifier is the leaf structure; Spinifex has soft, silvery-haired leaves that feel silky to the touch, whereas Marram leaves are smooth, stiff, and ribbed on the upper surface. Furthermore, Marram forms thick, vertical clumps, while Spinifex grows in long, horizontal runners that "walk" across the sand.

Ecological Impacts: Why Marram is Now Considered a Pest

While Marram was originally a hero of stabilization, it is now recognized as a significant threat to the ecological health of New Zealand's coastal margins. The primary issue lies in the plant's efficiency: it traps sand so effectively that it builds excessively high dunes that act as a wall, preventing sand from replenishing the land behind them. This lack of sand flow causes the landward side of the dunes to "starve," leading to the loss of specialized habitats like dune slacks where rare native orchids and insects thrive. Additionally, the steep Marram dunes are prone to "scarping" during storm events; rather than absorbing wave energy by shifting, the hard wall of sand collapses in large chunks, leading to rapid coastal erosion.

• Habitat Loss: Displacement of the native Pingao (Ficinia spiralis) and Spinifex (Spinifex sericeus).
• Geomorphological Alteration: Creation of "stagnant" dunes that no longer respond naturally to sea-level changes.
• Increased Vulnerability: Steep dunes are more susceptible to catastrophic failure during high-energy swells.
• Biodiversity Decline: Reduced nesting sites for coastal birds like the New Zealand Dotterel.

Habitat Loss: Displacement of the native Pingao (Ficinia spiralis) and Spinifex (Spinifex sericeus).

Geomorphological Alteration: Creation of "stagnant" dunes that no longer respond naturally to sea-level changes.

Increased Vulnerability: Steep dunes are more susceptible to catastrophic failure during high-energy swells.

Biodiversity Decline: Reduced nesting sites for coastal birds like the New Zealand Dotterel.

Restricted to Foredune

Erosion of inland dune systems

Monoculture dominance

Loss of rare coastal flora

Reduced visibility for birds

Increased predation on shorebirds

Brittle/Scarping

Structural damage to coastal property

Management Strategies: Removing Marram Successfully

Removing Marram is a labor-intensive process that requires a multi-year commitment to ensure the seed bank is exhausted and rhizomes do not resprout. In New Zealand, the most common method for large-scale removal is the targeted application of herbicides specifically formulated for grasses, which allows native broadleaf plants to survive. Mechanical removal using excavators is also an option for heavily infested areas, though this must be followed by immediate replanting of native species to prevent the dune from blowing away. Community-led "Dune Care" groups often use manual digging for small patches, which is effective but requires careful disposal of the rhizomes to prevent them from taking root elsewhere.

Chemical Control and Safety Protocols

When using herbicides like Gallant or Haloxyfop, it is essential to follow the New Zealand Environmental Protection Authority (EPA) guidelines to prevent runoff into the marine environment. Spraying should occur during active growth periods, typically in late spring or early autumn, to ensure the chemical is drawn down into the deep root system of the Marram grass.

Native Alternatives: Restoring the Natural Balance

The cornerstone of any Marram removal project must be the reintroduction of native sand-binders: Spinifex and Pingao. Spinifex (Spinifex sericeus) is the primary colonizer on the seaward face of the dune, using its long runners to catch sand and build low-angled, resilient mounds. Pingao (Ficinia spiralis), with its iconic golden-orange foliage, is equally vital and holds high cultural significance for Māori as a traditional weaving material. Unlike Marram, these native plants allow sand to move through the dune system, creating a "living" coastline that can adapt to the rising sea levels associated with climate change. Successful restoration projects in New Zealand have demonstrated that once Marram is removed, these native species can quickly re-establish and provide superior coastal protection. Marram grass is a species of grass that is native to the coastlines of Europe and North Africa but has become a significant invasive species in New Zealand. Read more in Wikipedia.

• Spinifex (Spinifex sericeus): Best for the front of the dune; highly salt-tolerant.
• Pingao (Ficinia spiralis): Iconic golden color; excellent for stabilization and biodiversity.
• Sand Tussock (Austrofestuca littoralis): A secondary binder for the mid-dune area. | Native Species | Planting Zone | Growth Habit | Cultural Use | | :— | :— | :— | :— | | Spinifex | Foredune | Long runners | Soil health | | Pingao | Foredune/Mid-dune | Clumping/Rhizome | Weaving (Raranga) | | Wiwi | Back-dune | Dense Rush | Thatching |

Spinifex (Spinifex sericeus): Best for the front of the dune; highly salt-tolerant.

Pingao (Ficinia spiralis): Iconic golden color; excellent for stabilization and biodiversity.

Sand Tussock (Austrofestuca littoralis): A secondary binder for the mid-dune area. | Native Species | Planting Zone | Growth Habit | Cultural Use | | :— | :— | :— | :— | | Spinifex | Foredune | Long runners | Soil health | | Pingao | Foredune/Mid-dune | Clumping/Rhizome | Weaving (Raranga) | | Wiwi | Back-dune | Dense Rush | Thatching |

Case Study: Successful Marram Eradication in the Manawatu

The Manawatu coastline has been the site of some of New Zealand's most ambitious Marram eradication efforts. Historically, this region suffered from massive "sand blows" that were stabilized with Marram, resulting in a wall of vegetation that cut off the inland ecosystem. Local councils and Department of Conservation (DOC) teams initiated a large-scale spray program, followed by the community planting of over 50,000 native seedlings. Within five years, the dune profile shifted from a steep, scarped cliff to a gentle slope that successfully absorbed storm surges during the 2023 weather events. This project serves as a blueprint for other New Zealand regions, proving that ecological restoration and coastal protection are not mutually exclusive.

Monitoring and Long-term Success

Success in the Manawatu was attributed to a rigorous monitoring program that used drones to identify resprouting Marram patches. This allowed for "spot-spraying" before the grass could set seed, drastically reducing the cost of maintenance in the subsequent years.

The Economic Impact of Marram on Coastal Infrastructure

From a financial perspective, Marram grass represents a hidden cost for many New Zealand coastal councils. While the initial planting was cheap, the long-term maintenance of the steep, unstable dunes it creates is expensive. When Marram dunes scarp during storms, they often leave infrastructure like boardwalks, pipes, and roads exposed to the sea. Native dunes, by contrast, are self-repairing; they "slump" during storms and rebuild themselves as sand returns in the summer. Transitioning from Marram to native vegetation is increasingly seen as a cost-effective "nature-based solution" for coastal hazard management in the face of increasing storm frequency.

• Infrastructure Repair: High costs associated with fixing scarped dunes and damaged walkways.
• Property Values: Stable, aesthetically pleasing native dunes often correlate with higher coastal property values.
• Council Rates: Savings on long-term coastal engineering by utilizing native sand-binders.
• Tourism: Enhanced natural beauty of gold and silver dunes attracts visitors to regional beaches.

Infrastructure Repair: High costs associated with fixing scarped dunes and damaged walkways.

Property Values: Stable, aesthetically pleasing native dunes often correlate with higher coastal property values.

Council Rates: Savings on long-term coastal engineering by utilizing native sand-binders.

Tourism: Enhanced natural beauty of gold and silver dunes attracts visitors to regional beaches.

Low

Moderate

High (Engineering required)

Low (Natural recovery)

High

Low (Scarping risk)

High (Adaptive)

Climate Change and Marram: A Modern Conflict

As New Zealand grapples with sea-level rise, the rigidity of Marram dunes has become a liability. Coastal squeeze—where the beach is trapped between the rising sea and a hard inland boundary—is exacerbated by Marram. Because Marram dunes do not move, the beach in front of them is often washed away during high tides, leaving no space for public recreation or wildlife. Ecological restoration that replaces Marram with Spinifex allows the dunes to "roll back" landward as the sea rises, preserving the beach environment for future generations. This adaptive management strategy is now a central pillar of New Zealand's national coastal policy statement.

Adaptive Management in Practice

Adaptive management involves removing Marram and "re-contouring" the dunes to a lower profile. This allows waves to occasionally overtop the foredune, depositing sand and nutrients into the back-dune area, which mimics the natural processes that existed before the 19th-century Marram introductions.

Community Engagement: How to Get Involved

Managing Marram in New Zealand is not just a job for scientists; it relies heavily on the "Coastcare" movement. Throughout the country, local volunteers meet regularly to "weed" Marram and plant natives. These groups provide the necessary eyes on the ground to spot new infestations and the labor to plant thousands of Spinifex and Pingao seedlings. For property owners, joining a local group provides access to expert advice and often subsidized plants and materials for dune restoration on their own land.

• Volunteer Groups: Regional councils often coordinate Coastcare groups; check your local council website.
• Educational Workshops: Learn to identify coastal weeds and master native planting techniques.
• Citizen Science: Use apps like iNaturalist to record Marram locations and native recovery progress.
• Corporate Volunteering: Many NZ businesses now participate in dune planting as part of their sustainability goals.

Volunteer Groups: Regional councils often coordinate Coastcare groups; check your local council website.

Educational Workshops: Learn to identify coastal weeds and master native planting techniques.

Citizen Science: Use apps like iNaturalist to record Marram locations and native recovery progress.

Corporate Volunteering: Many NZ businesses now participate in dune planting as part of their sustainability goals.

Coastcare BoP

Spinifex restoration

Beachcare

Biodiversity monitoring

Coastal Restoration Trust

Large scale re-contouring

Pest Free Auckland

Invasive weed removal

Technical Appendix: Chemical Application Rates

For professional contractors and advanced landowners, understanding the specific application rates for Marram control is vital for successful eradication. Using a knapsack sprayer, a common mix includes 150ml of Haloxyfop per 10 liters of water, combined with a non-ionic surfactant to ensure the chemical sticks to the waxy Marram leaves. It is important to avoid spraying during windy conditions to prevent "drift" onto nearby native broadleaf shrubs like Coprosma or Muehlenbeckia.

Timing the Kill

The best results are achieved when the plant is under slight stress but still actively growing. This ensures the herbicide is translocated to the deep rhizomes, which can extend several meters below the sand surface. A follow-up spray is almost always required 6–12 months later to catch seedlings and any surviving rhizome fragments.

Final Thoughts

The story of Marram grass in New Zealand is a profound lesson in unintended consequences. What began as a well-intentioned effort to stabilize the land has become a challenge to our natural heritage and coastal resilience. However, the path forward is clear: by replacing this invasive European species with our resilient native sand-binders, we can restore the dynamic, beautiful, and protective dunes that define the New Zealand coast. Whether you are a weekend beach-goer, a coastal resident, or a policy maker, understanding the role of Marram is essential for the stewardship of our "Long White Cloud" coastlines.

FAQ

Is Marram grass native to New Zealand?

No, it is native to Europe and North Africa and was introduced in the 1800s.

Why is Marram grass a problem now?

It creates steep, unstable dunes that outcompete native plants and disrupt natural sand flow.

How can I tell the difference between Marram and Spinifex?

Marram has stiff, ribbed, upright leaves; Spinifex has soft, silvery, horizontal runners.

Can I pull Marram out by hand?

Small patches can be dug out, but you must remove all rhizomes or it will regrow.

What is the best way to kill large areas of Marram?

Targeted herbicide spraying by professionals is currently the most effective method.

Is Pingao better than Marram?

Ecologically, yes. Pingao allows dunes to be dynamic and resilient to sea-level rise.

Does Marram grass provide good storm protection?

Initially yes, but in the long term, it creates "brittle" dunes that collapse during major storms.

What is a "skunked" dune?

This is a term used when a dune has failed to reach a point of stability due to invasive species like Marram.

Can I get native plants for free?

Many local councils provide free native plants to recognized Coastcare groups.

Does Marram grass affect bird nesting?

Yes, its dense growth reduces the open sandy areas required by birds like the NZ Dotterel.