Sand Gunnera

Gunnera dentata

Not Threatened

Last updated: 16 October 2026

Sand gunnera (Gunnera dentata) is a small, creeping endemic herb that forms low mats of toothed leaves only 1 to 4 cm long. It spreads by stout runners through damp sand and wet open ground, including coastal dune hollows, stream and river margins, and up into the mountains. Male and female flowers are on separate plants, and female plants carry stalks of pear-shaped fruit that ripen from pale yellow to deep orange, usually held above the leaves. It is a miniature relative of the giant gunneras sold as ornamentals, and it makes an unusual native groundcover for wet spots. Explore more native ground covers in our native plant guide.

Sand Gunnera (Gunnera dentata) in its natural habitat — Image credit: Sand Gunnera (*Gunnera dentata*) - photo by Wikipedia contributors, via Wikipedia

Plant Description

Gunnera dentata is a low, creeping, dioecious herb that spreads by stout, branched runners (stolons) which often travel through sand just below the surface. The leaves are 1 to 4 cm long, occasionally to 6 cm, with a leathery-textured blade that is usually ovate to elliptic, sometimes rounded or obovate. The margins are coarsely and often irregularly toothed or scalloped, which gives the species its name dentata, meaning toothed. Leaf colour ranges from grey-green to dark green or brownish.

Tiny greenish flowers appear from December to February on short spikes, with male and female flowers on separate plants. On female plants the fruits are drupes spaced along the stalk, elongated and pear-shaped, ripening from pale yellow to deep orange, with the flesh closely attached to the seed. The fruiting stalk is usually held above the leaves.

It can be separated from Gunnera prorepens, the other common native gunnera, by its toothed, firmer leaves and its fruits spaced out along the stalk. Gunnera prorepens has thinner, almost smooth-edged leaves with heart-shaped bases and fruits densely clustered at the top of the stalk.

Quick Facts

*Gunnera dentata* quick facts
Scientific Name	Gunnera dentata
Height	0.02-0.1 m
Spread	Runners to about 0.4 m, forming wider mats over time
Water Needs	High; consistently moist ground
Light	Full sun to light shade
Frost Tolerance	High; extends from the coast to low alpine sites
Salt Tolerance	Some; grows in coastal dune hollows and near tidal river margins
Growth Rate	Moderate
Lifespan	Perennial

Climate Best Suited to

Suits cool to mild, moist climates and tolerates exposed, windy and cold sites, from coastal dunes to low alpine ground, provided the soil stays damp.

Regional Suitability

City suitability for *Gunnera dentata*
City	Climate Suitability
Auckland	Medium
Wellington	High
Christchurch	Medium
Dunedin	High

Plant Habitat

Sand gunnera is endemic to New Zealand and occurs from the Pouto Peninsula on the Northland west coast southwards through both main islands, mainly in western districts. Its distribution is local rather than continuous, and it is uncommon in some regions such as Auckland and Otago.

It grows in open, damp places from the coast to low alpine areas: damp sand, dune slacks and swales, the margins of streams and tidal rivers, and wet grassland or seepages inland. Its runners let it colonise shifting, damp sand where few other plants can root.

Growing Requirements

Soil Requirements

In the wild it creeps through damp sand and silty or gravelly ground that stays moist.

Damp sand, sandy loam or gritty soil
Low to moderate fertility
Open ground without heavy competition

Light Requirements

It is a plant of open sites and grows most compactly in good light, although it tolerates some shade.

Full sun in cool or coastal gardens
Light shade in hot, dry districts

Water Requirements

Consistent moisture is essential. It will not survive long in ground that dries out.

Keep the soil damp year round
Well suited to seepages and pond or stream edges

Planting and Establishing

Plant in spring or autumn into damp, open ground such as a bog garden, the edge of a pond or a moist rockery pocket. Set plants about 20 to 30 cm apart and keep them free of competing grasses until the runners knit together.

To get fruit, plant several individuals of known sex, or at least a few unrelated plants, so that both male and female plants are present.

Ecological Role

The fleshy drupes are dispersed by fruit-eating animals and possibly ants, according to NZPCN; which animals eat them most is not well documented. Like other gunneras, it forms a partnership with nitrogen-fixing cyanobacteria (Nostoc), which helps it grow in poor, wet soils.

On damp sand and in dune slacks it is an early coloniser, its runners helping to bind loose sand. It is part of the low, open turf and herbfield communities of these naturally disturbed habitats.

Uses & Significance

Garden Uses

A low, unusual native groundcover for damp places where most groundcovers fail.

Bog gardens and pond margins
Damp rockeries and alpine troughs
Wetland and dune slack restoration
Containers kept moist

Ecological Value

It helps restore native turf in damp sand and wetland margins, and its fruit provides food for native wildlife.

Binds damp sand with its runners
Fruit eaten by native animals
Regionally uncommon in Auckland and Otago

Landscaping Uses

Use sand gunnera as a living carpet between stepping stones in a damp area, around the edge of a pond, or in a moist trough with other miniature natives. The orange fruit held above the toothed leaves gives a long-lasting summer display on female plants.

It combines well with other low wetland natives such as Pratia (Lobelia), Leptinella and small Selliera.

Seasonal Care Calendar

Spring

New leaves emerge and runners start to extend. Good time for planting and dividing.

Divide rooted runners
Weed around mats

Summer

Flowers appear from December to February, followed on female plants by pale yellow to orange fruit.

Keep soil moist
Collect ripe fruit for seed

Autumn

Fruit may persist into autumn. Mats continue to spread while soil is warm and damp.

Sow fresh seed
Plant new mats

Winter

Growth slows and leaves may become browner in cold weather, but plants remain evergreen in most sites.

Keep free of fallen leaves
Avoid waterlogging that becomes stagnant

When to Prune and How Much

No pruning is needed. Simply pull out any runners that wander beyond where they are wanted.

Remove dead leaves and debris that settle on the mat in autumn, as these can smother small plants.

How to Grow Sand Gunnera

Sand gunnera is most easily propagated by separating rooted lengths of runner, which establish quickly when replanted straight into moist ground. Fresh seed from ripe fruit on female plants is also viable and is the best way to raise a mix of male and female plants for fruiting. Keep all young plants consistently moist, because drying out is the most common cause of failure. Seedlings take time to reach fruiting size, and you will not know which are female until they flower, so raise several of them together.

By Division of Runners

Runners root at intervals along their length, so rooted pieces can be lifted from an established mat with little disturbance. This produces plants of the same sex as the parent.

In spring or autumn, locate a rooted section of runner
Cut it free with a few leaves and roots attached
Replant immediately into damp, sandy or gritty mix or directly in the garden
Keep moist and lightly shaded for a couple of weeks while it settles

From Seed

Collect fruit when it has turned deep orange. The flesh is closely attached to the seed, so sowing the whole fruit is practical.

Pick fully coloured fruit in summer
Squash or sow whole on the surface of a moist, gritty seed mix
Cover lightly with fine grit
Keep the tray constantly damp in a cool, bright place
Prick out seedlings into individual pots once they have several leaves

Pests & Diseases

Few pests are recorded on sand gunnera in cultivation. Slugs and snails may damage young leaves, and plants can be overgrown by vigorous grasses.

In the wild, drainage of wetlands, dune stabilisation with exotic grasses and weed invasion of damp sand habitats are the main pressures.

Cultural Significance

No Māori name or traditional Māori use is recorded for Gunnera dentata in the sources consulted.

The genus Gunnera honours the Norwegian bishop and botanist Johan Ernst Gunnerus. Thomas Kirk described Gunnera dentata in 1895, and Thomas Cheeseman's name Gunnera arenaria, meaning of sand, is now treated as a synonym.

Bonus Tip

If you buy sand gunnera for its orange fruit, ask the nursery for a female plant and a male plant. Propagation by runners keeps the sex of the parent, so a mat grown from one division will never fruit on its own.

Plant Conservation

Gunnera dentata is ranked Not Threatened nationally (2023), although the Flora of New Zealand notes it as declining. Regionally it is listed as Regionally Endangered in Auckland and Regionally Naturally Uncommon in Otago, and its status in Northland is Data Deficient.

Protecting dune slacks, seepages and natural river margins from drainage, grazing and weed invasion is the main way to keep it. Planting it in wetland and dune restoration projects can help re-establish local populations.

Frequently Asked Questions

Is Gunnera dentata related to giant gunnera?

Yes, it belongs to the same genus as the huge South American Gunnera tinctoria, a pest plant in New Zealand, but sand gunnera is a native ground-hugging herb with leaves only a few centimetres long.

Why does my Gunnera dentata not produce berries?

Male and female flowers are borne on separate plants, so a female plant needs a male growing nearby to set its yellow to orange fruit.

Where does sand gunnera grow naturally?

It is endemic to New Zealand and grows on damp sand, dune slacks, stream and river margins and wet open ground, mainly in western districts from the Pouto Peninsula south.

Sources and Further Reading

The botanical, growing, and conservation details for Sand Gunnera (Gunnera dentata) on this page draw on the New Zealand plant references below. Consult them for full technical records and the latest distribution data.