Campbell Island Poa
Poa aucklandica subsp. campbellensis
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Campbell Island poa (Poa aucklandica subsp. campbellensis) is a tiny tufted grass with stiff, inrolled leaves just 2 to 5 cm long and close-packed flowering stems usually 2 to 10 cm tall. It is endemic to Campbell Island/Motu Ihupuku in New Zealand's subantarctic, where it grows in upland rocky herbfield. It is the smallest of the three subspecies of Poa aucklandica, the others growing on the Auckland Islands and on Mount Anglem, Stewart Island. It is ranked At Risk - Naturally Uncommon because it is an island endemic known from one location, though it is abundant where it occurs. Explore more native grasses and flaxes in our native plant guide.
Plant Description
Campbell Island poa is a slender perennial grass with short rhizomes that forms small, dense tufts of close-packed culms. The leaf-sheaths are hairless and the ligule is short, 0.3 to 1 mm long. The leaf-blades are stiff and inrolled, 2 to 5 cm long and only 0.5 to 1.5 mm wide, held upright.
The flowering stems are 2 to 10 cm tall and carry a lax panicle 1.5 to 5 cm long with spikelets 4.5 to 6.5 mm long, each with three to five florets. NZPCN notes a small callus at the base of each floret bearing crinkled hairs.
It differs from Poa aucklandica subsp. aucklandica of the Auckland Islands, which has soft, flaccid leaves and taller culms, and from subsp. rakiura of Mount Anglem on Stewart Island, which is taller again. Its stiff, inrolled leaves and very compact tufts are the best field features.
Quick Facts
| Scientific Name | Poa aucklandica subsp. campbellensis |
|---|---|
| Height | Flowering stems about 2-10 cm |
| Spread | Small, close-packed tufts |
| Water Needs | Moist; very wet subantarctic climate |
| Light | Open upland rocky sites |
| Frost Tolerance | Good; an upland subantarctic grass |
| Salt Tolerance | No reliable information |
| Growth Rate | No reliable information |
| Lifespan | Perennial |
Climate Best Suited to
Suits the cold, wet, windy and very cloudy upland climate of Campbell Island, where summers are cool and sunshine is rare. It is not suited to warm or dry places.
Regional Suitability
| City | Climate Suitability |
|---|---|
| Auckland | Low |
| Wellington | Low |
| Christchurch | Low |
| Dunedin | Low |
Plant Habitat
This subspecies is endemic to Campbell Island/Motu Ihupuku, the southernmost of New Zealand's subantarctic island groups. It is known from that island alone.
It grows in upland rocky herbfield, where its small, tight tufts fit among rocks and low herbs on the exposed tops.
Growing Requirements
Soil Requirements
It grows in thin peaty soil among rocks in upland herbfield.
- Shallow, moist, organic soil
- Rocky ground
- Low fertility
Light Requirements
Its habitat is open and treeless, but Campbell Island has very little sunshine, so the light is mostly diffuse.
- Open rocky herbfield
- Adapted to frequent cloud
Water Requirements
Rain or drizzle falls on most days on Campbell Island, keeping the ground damp.
- Needs reliable moisture
- Would suffer in drought
Planting and Establishing
Campbell Island poa is not commercially available and NZPCN records propagation as not known. Campbell Island is a nature reserve with restricted access, so plants must not be collected.
It is of interest to botanists and conservation programmes only. Gardeners wanting a tiny native grass for a trough or rock garden should look for mainland alpine Poa species raised by specialist nurseries.
Ecological Role
Campbell Island poa forms part of the low cover of grasses and herbs in upland rocky herbfield. Like other Poa species it is wind-pollinated, but its flowering and fruiting times have not been recorded because it has been insufficiently studied and collected.
Vegetation on Campbell Island recovered markedly after feral sheep were removed between 1970 and 1991 and rats were eradicated in 2001, changes that benefited native grasses and herbs generally.
Uses & Significance
Garden Uses
It has no garden use because it is not cultivated and its needs in cultivation are not known.
- Of scientific interest only
- Not commercially available
Ecological Value
It adds to the diversity of endemic grasses on Campbell Island and helps cover thin soils among rocks on the uplands.
- Island endemic subspecies
- Part of upland herbfield
Landscaping Uses
This grass has no landscaping use. Its tight little tufts among rocks on the Campbell Island uplands are best seen in the wild.
For a similar miniature effect in a mainland alpine trough, choose a small native grass that is already in cultivation.
Seasonal Care Calendar
Spring
New growth begins as the short subantarctic growing season starts.
- Growth resumes
- Flowering season not documented
Summer
The main growing period on the island, although exact flowering months are not known.
- Active growth
- Panicles may appear
Autumn
Growth slows as the weather cools.
- Growth slows
- Old culms wither
Winter
The small tufts persist through the cold, windy winter.
- Little growth
- Exposed to wind and cold
When to Prune and How Much
No pruning is needed. In cultivation, dead leaves could simply be pulled out by hand.
Because the tufts are so small, avoid cutting into them.
How to Grow Campbell Island Poa
NZPCN records propagation of Poa aucklandica subsp. campbellensis as not known, and the subspecies is not grown commercially. Campbell Island is a nature reserve within the New Zealand Subantarctic Islands World Heritage Area, and any collection of seed or plants needs a permit. The approaches below are those used for small tufted Poa species in general and would be a starting point for a botanic garden or conservation programme rather than tested methods for this subspecies.
From Seed
Each spikelet carries three to five florets. Since the flowering and fruiting season is not known, the timing of seed collection would need to be worked out by observation. As a grass of a cold climate, it is sensible to germinate seed in cool rather than heated conditions.
- Collect ripe panicles from cultivated plants or under permit
- Sow on a moist, gritty seed mix and cover very lightly
- Keep cool and evenly moist
- Prick out seedlings into small pots when they can be handled
- Grow on in a cool, bright place
By Division
The plant has short rhizomes and forms tufts, so established cultivated plants could be split. Because the tufts are small, divisions should be kept as large as practical, with plenty of roots, so they do not dry out.
- Lift a healthy cultivated tuft in cool, moist weather
- Separate rooted portions, each with several shoots
- Pot into a gritty mix with some organic matter
- Keep cool and lightly shaded until new growth shows
Pests & Diseases
No pests or diseases specific to this grass are recorded. Introduced sheep and Norway rats once modified Campbell Island's vegetation, but both have been removed.
In cultivation, warmth and drought would be bigger problems than pests.
Cultural Significance
No Māori name or traditional Māori use is recorded for Campbell Island poa in the sources consulted.
The subspecies name campbellensis means of Campbell Island. It was formerly treated as Poa kirkii var. campbellensis, a variety of the mainland Poa kirkii, before being placed within Poa aucklandica.
Bonus Tip
On a visit to the Campbell Island uplands, look at leaf texture to identify this grass: its leaves are stiff and rolled inwards like fine wires, quite unlike the soft, flat leaves of the Auckland Islands subspecies.
Related Plants
Explore other native plants that share similar characteristics or habitats with Campbell Island Poa (Poa aucklandica subsp. campbellensis), offering further insights into New Zealand's diverse flora. These related species provide context and opportunities for complementary planting in your garden.
Plant Conservation
Poa aucklandica subsp. campbellensis is ranked At Risk - Naturally Uncommon (2023) with the qualifiers Island Endemic and One Location. NZPCN states that it is not threatened and is abundant within its known habitats.
Campbell Island is a nature reserve and part of a World Heritage Area. The eradication of sheep and rats, and strict biosecurity to keep new pests and weeds out, are what secure its future.
Frequently Asked Questions
Where is Campbell Island poa found?
It is endemic to Campbell Island/Motu Ihupuku, New Zealand's southernmost subantarctic island group, where it grows in upland rocky herbfield.
How does Campbell Island poa differ from Auckland Island poa?
Campbell Island poa forms smaller, denser tufts with shorter flowering stems, a shorter ligule and stiff, inrolled leaves 2 to 5 cm long, whereas Auckland Island poa has soft, flaccid leaves up to 16 cm.
Is Poa aucklandica subsp. campbellensis endangered?
No. It is ranked At Risk - Naturally Uncommon because it is a narrow-range island endemic, but NZPCN notes it is not threatened and is abundant within its known habitats.
Sources and Further Reading
The botanical, growing, and conservation details for Campbell Island Poa (Poa aucklandica subsp. campbellensis) on this page draw on the New Zealand plant references below. Consult them for full technical records and the latest distribution data.