Plants

Marine and coastal plants play an essential role in the health and resilience of Nelson’s coastline and near‑shore environments. From dune grasses and saltmarsh species to seaweeds and seagrass meadows, these plants stabilise coastlines, support wildlife, improve water quality, and help protect our communities from erosion and storms.

Many coastal and marine plants are specially adapted to harsh conditions — salt spray, shifting sands, strong winds, tidal movements, and nutrient‑poor soils. Some are nationally rare or declining, and several coastal plant communities in Nelson have been lost due to development, weeds, and historic land use.

Caring for these species and restoring coastal and marine vegetation helps strengthen the mauri of our coast and protects the habitats that support shorebirds, fish nurseries, lizards, and a wide range of marine life.

Dune Plants

Native dune plants bind and stabilise sand, forming natural buffers against coastal erosion and storms. They also provide habitat for dune insects and ground‑nesting birds such as the banded dotterel.

Key native dune species include:

Pīngao – a golden sand‑binder central to dune ecology and weaving traditions
Spinifex – fast‑spreading grass that traps and stabilises sand
Tauhinu – hardy shrub supporting lizards and insects
Sand coprosmas and other native groundcovers

Native dune vegetation is now largely absent in Nelson due to the spread of marram grass and coastal development. Restoration is underway at Tāhunanui Beach, Kokorua Spit, Delaware Inlet, and other sites.

Estuarine & Saltmarsh Plants

Estuaries and saltmarshes are among the most productive ecosystems in Aotearoa. These plants filter runoff, trap sediment, improve water quality, and provide critical habitat for fish, invertebrates, and coastal birds.

Common estuary‑edge plants include:

Oioi (jointed rush)
Sea rush (wiwi)
Glassworts (salt herbs)
Raupō (in upper estuary zones)
Saltmarsh ribbonwood
Coastal sedges and grasses

These species are found in the Waimea Inlet, Nelson Haven, Delaware Estuary, and Kokorua Estuary.

Rocky Shore & Cliff Plants

Rocky coastal environments support hardy plants that cling to cliffs, boulders, and shallow soils and help protect these slopes from erosion.

Common species include:

Taupata
Coastal flax (harakeke)
Native succulents
Coastal herbs and shrubs

These species occur along Cape Soucis, the Boulder Bank, and much of Nelson’s rocky coastline.

Seaweeds & Seagrass

Beneath the surface, marine plants form the foundation of coastal ecosystems.

Seaweeds (Macroalgae)

Seaweeds thrive on rocky reefs and intertidal zones, providing food and shelter for fish, invertebrates, penguins, seals, and other marine life.

Key groups include:

Brown seaweeds, including kelp forests
Red seaweeds, found in deeper or shaded areas
Green seaweeds, common on tidal flats and shallow rocky shores

The Horoirangi Marine Reserve protects significant reef systems supporting diverse seaweed communities.

Seagrass (Rimurēhia / Zostera muelleri)

Seagrass meadows grow in shallow estuaries such as the Waimea Inlet and Delaware Estuary. They are critical habitats because they:

Provide nurseries for juvenile fish (including kahawai, flounder, mullet)
Stabilise sediments and trap nutrients
Improve water clarity
Support shellfish beds
Absorb carbon (“blue carbon”)

Seagrass is highly sensitive to sedimentation, trampling, and poor water quality.

Threats to Coastal & Marine Plants

Invasive Weeds

Marram grass (out‑competes native dune plants)
Gorse and Spanish heath
Invasive coastal shrubs
Marine pests that smother seaweeds or disturb habitats

For more detail on Marine Pests head to our Marine Biosecurity page

Coastal Development

Past reclamation and land use changes have removed much of Nelson’s native coastal vegetation.

Sedimentation & Stormwater Runoff

Smothers seagrass beds, affects estuary plants, and changes substrate composition.

Human Disturbance

Trampling dunes
Creating informal tracks
Vehicles on beaches
Damage to seagrass beds from anchors or dragging kayaks

Climate Change

Sea‑level rise
Increased erosion
Storm surges
Loss of low‑lying plant communities

What Council Is Doing

Nelson City Council works with iwi, DOC, Tasman District Council, schools, landowners and local community groups to protect and restore marine and coastal vegetation. Our work includes:

Restoring native dune systems at Tāhunanui, Kokorua, and Delaware
Removing invasive weeds such as marram, gorse, and Spanish heath
Planting native dune, estuary, and coastal species in priority areas
Monitoring estuary‑edge vegetation and seagrass extent
Managing stormwater and reducing sediment impacts on coastal plants
Supporting stewardship of sensitive coastal habitats, including offshore islands and the Boulder Bank

This mahi strengthens coastal resilience and provides habitat for a wide range of marine and coastal species.

Major Programmes Supporting Coastal Plants

These long‑term initiatives contribute directly to coastal and marine plant restoration:

Nelson Nature – coastal and estuary restoration, weed control, and community support
Coastal & Estuary Monitoring and Restoration Programme
Waimea Inlet Strategy and Action Plan
Project Mahitahi – catchment‑to‑coast restoration
Halo Projects
Environmental Grants Programme

What Can You Do

Stay off dunes — use marked accessways
Take part in coastal or estuary planting days
Remove or report small invasive weeds
Avoid dumping garden waste in coastal areas
Clean shoes, tyres, and gear to avoid spreading seeds
Anchor with care to protect seagrass and seaweed beds
Avoid dragging kayaks over seagrass meadows
Support restoration groups working along the coast
Record plant sightings on iNaturalist

Small actions help protect fragile coastal and marine habitats.