Armstrong's Mountain Daisy (Celmisia armstrongii) hero image

Armstrong's Mountain Daisy

Celmisia armstrongii

Not Threatened

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Armstrong's mountain daisy (Celmisia armstrongii) is a large-leaved alpine daisy endemic to the South Island, easily recognised by its stiff, bronze-green leaves marked with a bright orange-brown stripe along the midrib. It forms carpets or clusters of rosettes with leaves 12 to 40 cm long, and from November to February sends up stems to 35 cm tall carrying big white daisies with yellow centres. It grows in wet montane to alpine grassland and herbfield from North-West Nelson to near Lake Wakatipu, mostly west of the Main Divide. It is Not Threatened and one of the easier large celmisias to grow. Explore more native flowering plants in our native plant guide.

Armstrong's Mountain Daisy (Celmisia armstrongii) in its natural habitat
Image credit: Armstrong's Mountain Daisy (C. armstrongii) - photo by Wikipedia contributors, via Wikipedia

Plant Description

Celmisia armstrongii is a moderately stout, woody-based herb that forms irregular carpets or, less often, clusters of one to eight rosettes. The leaves are linear-oblong, 120 to 400 mm long and 10 to 20 mm wide, leathery, at first erect and then spreading. The upper surface is bronze-green with a conspicuous orange-brown strip along the midrib, and the underside is densely clothed in white tomentum.

Flowering stems reach about 35 cm and each carries a single large head with 100 to 120 white ray florets and around 130 yellow disc florets. It flowers from November to February and fruits from January to April. The achenes are spindle-shaped to cylindrical, 4 to 5 mm long and moderately to densely hairy, with a pappus that is carried by the wind.

It belongs to the Celmisia coriacea group of large-leaved mountain daisies. It is separated from Celmisia coriacea by its narrower leaves, under 20 mm wide, and the orange midrib stripe makes it one of the most recognisable members of the group.

Quick Facts

Celmisia armstrongii quick facts
Scientific Name Celmisia armstrongii
Height Leaves 12 to 40 cm; flower stems to 35 cm
Spread Irregular carpets or clusters of up to eight rosettes
Water Needs High; permanently moist soil
Light Shade to semi-shade in gardens
Frost Tolerance High; montane to alpine
Salt Tolerance Low; a mountain species
Growth Rate Slow to moderate
Lifespan Long-lived perennial

Climate Best Suited to

Suits cool, very wet mountain climates with high rainfall, frequent cloud and winter snow, such as the western side of the Southern Alps.

Regional Suitability

City suitability for Celmisia armstrongii
City Climate Suitability
Auckland Low
Wellington Medium
Christchurch Medium
Dunedin High

Plant Habitat

Celmisia armstrongii is endemic to the South Island. It ranges from North-West Nelson south along the Southern Alps to Mt Bonpland near Lake Wakatipu, and is most abundant west of the Main Divide.

It is a montane to alpine plant of high rainfall areas, where it is common in wet grassland and herbfield. In places it forms extensive carpets among snow tussocks and other herbs.

Growing Requirements

Soil Requirements

NZPCN recommends permanently moist, free-draining, acidic soil, matching the leached mountain soils of the western ranges.

  • Add peat, leaf mould or fine bark to increase acidity and moisture retention
  • Include grit for drainage
  • Avoid lime and heavy clay

Light Requirements

In gardens it is easily grown in shade, which keeps its roots cool and moist.

  • Shade or semi-shade in lowland gardens
  • Avoid hot, dry, sunny positions

Water Requirements

It needs a constant supply of moisture and will suffer if the soil dries.

  • Water regularly through summer
  • Mulch with gravel to retain moisture without rotting the crown

Planting and Establishing

Plant in autumn or early spring in a shaded, cool position such as the south side of a rock garden or a raised peat bed. Set the rosettes at soil level and firm gently.

Allow space for it to spread into a carpet of rosettes. It is occasionally available from specialist native plant nurseries; buy nursery-grown plants rather than collecting from the wild.

Ecological Role

Its large white daisies are visited by the native flies, bees and moths that pollinate many alpine flowers, although specific pollinators of this species are not documented. The wind-carried seeds can colonise open patches in wet grassland.

In western alpine herbfields it is a conspicuous member of the large-leaved Celmisia community and contributes to the dense ground cover that protects soils on steep, wet slopes.

Uses & Significance

Garden Uses

A striking foliage and flowering plant for cool, moist gardens, admired for its orange-striped leaves.

  • Shaded rock gardens
  • Raised peat beds
  • Alpine and native plant collections

Ecological Value

An important component of western South Island alpine grassland and herbfield.

  • Large flowers provide nectar and pollen for alpine insects
  • Carpets of rosettes protect wet mountain soils
  • Part of the diverse Celmisia flora of the Southern Alps

Landscaping Uses

Use its upright, sword-like bronze leaves as a textural feature in a cool rockery, contrasting them with small-leaved hebes, mosses and ferns. The white daisies lift the planting in early summer.

Planted in drifts in a moist, shady bed, it can recreate the look of a West Coast alpine herbfield.

Seasonal Care Calendar

Spring

New leaves emerge and flower buds form late in the season.

  • Top up acidic mulch
  • Watch for slugs on new growth

Summer

Flowering runs from November to February.

  • Keep soil moist
  • Deadhead if seed is not wanted

Autumn

Seed ripens from January to April.

  • Collect and sow fresh seed
  • Plant new rosettes

Winter

Rosettes persist through cold weather; in the wild they lie under snow.

  • Ensure drainage remains good
  • Remove dead leaves that trap moisture

When to Prune and How Much

No pruning is required. Remove spent flower stems at the base once flowering finishes.

Clear away old, dead leaves from around the rosettes to keep the crowns healthy.

How to Grow Armstrong's Mountain Daisy

Celmisia armstrongii is best grown from fresh seed, according to NZPCN, which recommends sowing immediately or stratifying the seed for one to three months. Established carpets with several rosettes can also be divided. Plants raised in cultivation should be kept in shaded, permanently moist conditions from the start, since young plants dry out quickly.

From Seed

Seed ripens from January to April. Fresh seed can be sown at once, or held moist and cold for one to three months to mimic a mountain winter before sowing in spring.

  1. Collect seed heads as the pappus fluffs out
  2. Either sow immediately or mix seed with damp sand and keep in a refrigerator for one to three months
  3. Sow on the surface of an acidic, free-draining seed mix
  4. Cover lightly with fine grit and keep evenly moist in shade
  5. Prick out seedlings into deep pots once they have a few true leaves
  6. Grow on in shade until well rooted before planting out

By Division

Rosettes in a carpet each develop their own roots and can be separated, which gives a mature-looking plant more quickly than seed.

Division is also the only way to keep a particularly fine form, for example one with an especially bright midrib stripe, true to type.

  1. Divide in early autumn or early spring
  2. Lift a section of the carpet with soil around the roots
  3. Separate rosettes that each have healthy roots
  4. Pot into acidic, gritty mix and keep shaded and moist until new growth appears

Pests & Diseases

Slugs and snails may chew young leaves and seedlings. In warm, humid lowland conditions crown rot can develop, especially if the plant is grown in sun and kept wet without good drainage.

NZPCN notes that it dislikes humidity, so good air flow is important in sheltered gardens.

Cultural Significance

No Māori name or traditional use is recorded specifically for Celmisia armstrongii. It was described by Donald Petrie in 1893 to 1894.

The name honours Joseph Francis Armstrong, a gardener and plant collector, or his son John Beattie Armstrong, both of whom collected plants in Canterbury and elsewhere in the late nineteenth century.

Bonus Tip

To show off the orange midrib stripe, plant it where low sun shines through or across the leaves, such as at the edge of a path in a shaded rockery that catches early morning light.

Plant Conservation

Celmisia armstrongii is ranked Not Threatened and has been at every assessment since 2004. Otago's 2025 regional assessment also rates it Regionally Not Threatened.

It is widespread and common in the wet western mountains, much of which lies within national parks and conservation land. Controlling browsing animals such as deer and chamois helps keep alpine herbfields healthy.

Frequently Asked Questions

How do you identify Celmisia armstrongii?

Look for long, narrow, leathery bronze-green leaves with a conspicuous orange-brown strip along the midrib and dense white tomentum underneath. It differs from Celmisia coriacea in having leaves narrower than 20 mm.

Where does Armstrong's mountain daisy grow?

It grows from North-West Nelson south to Mt Bonpland near Lake Wakatipu, mostly west of the Main Divide in high rainfall areas, in wet grassland and herbfield.

How do you grow Celmisia armstrongii from seed?

NZPCN advises sowing fresh seed immediately or stratifying it for one to three months, then growing seedlings in shaded, permanently moist, free-draining, acidic soil.

Who was Celmisia armstrongii named after?

It honours either Joseph Francis Armstrong (1820 to 1902), a gardener and plant collector, or his son John Beattie Armstrong (1850 to 1926).

Sources and Further Reading

The botanical, growing, and conservation details for Armstrong's Mountain Daisy (Celmisia armstrongii) on this page draw on the New Zealand plant references below. Consult them for full technical records and the latest distribution data.