Silky Mountain Daisy (<i>Celmisia holosericea</i>) hero image

Silky Mountain Daisy

Celmisia holosericea

Not Threatened

This native plant, known as Silky Mountain Daisy (scientific name: Celmisia holosericea ), is a remarkable species endemic to New Zealand. It is characterized by its unique features, ecological role, and cultural significance. This comprehensive guide provides detailed information on its care, propagation, and importance within the New Zealand ecosystem. Understanding this plant contributes to the appreciation of our rich biodiversity and heritage, and supports conservation efforts for Alpine Plants .

Silky Mountain Daisy (<i>Celmisia holosericea</i>) showing its silvery, narrow leaves and white daisy-like flowers
Image credit: Silky Mountain Daisy ( Celmisia holosericea ) - photo by Wikipedia contributors, via Wikipedia

Plant Description

Celmisia holosericea , commonly known as the Silky Mountain Daisy, is an elegant perennial subshrub endemic to the South Island of New Zealand, particularly abundant in Fiordland. This species forms attractive rosettes of narrow, leathery leaves that are uniquely covered in a dense, silvery-white, silky tomentum on both surfaces, giving it a distinctive shimmering appearance. The foliage provides excellent contrast in rock gardens and alpine settings. In late spring to summer, it produces delicate white, daisy-like flowers with yellow centers, held above the foliage on short stems. Its ability to grow in varied habitats from coastal to subalpine areas highlights its adaptability.

Quick Facts

Celmisia holosericea quick facts
Scientific Name Celmisia holosericea
Height 0.10-0.25 metres
Spread 0.30-0.50 metres
Water Needs Moderate; requires consistent moisture but dislikes waterlogging
Light Full sun to partial shade
Frost Tolerance High
Salt Tolerance Moderate
Growth Rate Slow
Lifespan 10-25 years

Climate Best Suited to

The Silky Mountain Daisy is surprisingly adaptable, thriving in a range of New Zealand climates from coastal to lower subalpine zones. It is tolerant of frost and cool temperatures, making it well-suited for many South Island gardens. While it prefers cool, moist conditions, it requires good air circulation and well-drained soil to prevent issues in more humid or warmer environments. It can also tolerate coastal exposure, resisting salt spray and wind.

Regional Suitability

City suitability for Silky Mountain Daisy
City Climate Suitability
Auckland Good (with good drainage)
Wellington Excellent
Christchurch Excellent
Dunedin Excellent
Invercargill Excellent

Plant Habitat

Celmisia holosericea is widespread in Fiordland, New Zealand, where it inhabits a diverse range of environments. It can be found in coastal areas, lowland rocky places, and up to lower subalpine zones. Its natural habitats include grasslands, herb-fields, and rocky outcrops, often in situations with good drainage and some exposure. Observations show it thriving on northerly slopes and in damp hollows, demonstrating its adaptability to both drier and wetter microclimates within its range.

Growing Requirements

Soil Requirements

Prefers moist, well-drained, gritty soil. It can tolerate poorer soils but good drainage is essential to prevent root rot.

  • Moist, well-drained, gritty soil
  • Tolerant of various soil types
  • Good air circulation around roots

Light Requirements

Grows well in full sun to partial shade. In hotter climates, some afternoon shade can be beneficial to prevent leaf scorch.

  • Full sun for best growth
  • Partial shade in hot areas
  • Avoid deep, stagnant shade

Water Requirements

Planting and Establishing

Plant Silky Mountain Daisy in a well-drained location, such as a rock garden, raised bed, or a sloping site. Incorporate plenty of grit or pumice into the soil to enhance drainage. Plant with the crown slightly above ground level and backfill, ensuring good contact with the roots. Water in well. A top-dressing of fine gravel around the plant will help to keep the foliage dry, mimic its natural habitat, and prevent collar rot. Ensure good air circulation around the plant, especially in more humid environments.

Ecological Role

Celmisia holosericea plays a vital ecological role in New Zealand's alpine ecosystems, particularly in the drier eastern mountain ranges. This distinctive mountain daisy supports native pollinator communities by providing nectar and pollen during the critical alpine flowering season from December to March. Native flies, moths, beetles, and short-tongued bees depend on these flowers when few other food sources are available at high altitudes.

The plant's densely hairy leaves and stems, which give it its characteristic hoary appearance, create unique microenvironments that shelter small invertebrates from harsh alpine conditions. Its deep taproot system contributes to soil stabilization on loose screes and rocky outcrops, while also accessing moisture from deep soil layers during dry periods. This adaptation allows it to persist in exposed sites where it helps establish and maintain alpine plant communities.

Uses & Significance

Garden Uses

Excellent for rock gardens, alpine beds, and containers. Its silvery foliage provides an attractive contrast with other plants and is striking year-round.

  • Rock gardens and alpine beds
  • Containers and troughs
  • Foliage plant for contrast

Ecological Value

Its small white flowers provide nectar for various native insects, contributing to the biodiversity of its natural habitats.

  • Nectar source for native insects
  • Habitat for small ground-dwelling fauna
  • Soil stabilization

Landscaping Uses

Ideal for creating texture and contrast in native plant landscapes, particularly in areas where a low-growing, silvery-foliaged plant is desired. It can be mass-planted for a shimmering effect.

Seasonal Care Calendar

Spring

Remove any dead or discoloured leaves from the previous season to encourage new growth and maintain good air circulation. A very light, low-nitrogen fertilizer can be applied.

  • Clear old foliage
  • Light low-nitrogen feed
  • Ensure good air flow

Summer

Monitor soil moisture and water deeply during dry periods. Check for pests like mealybugs, which can be an issue in sheltered spots.

  • Water deeply in dry spells
  • Monitor for pests
  • Avoid stagnant humidity

Autumn

After flowering, spent flower stalks can be removed for neatness. Ensure adequate drainage before the onset of winter rains.

  • Remove spent flowers
  • Check drainage
  • Prepare for winter moisture

Winter

Being hardy, it requires minimal attention in winter. Ensure drainage is maintained to prevent waterlogging.

  • Minimal maintenance
  • Protect from excessive wetness
  • Resistant to cold and snow

When to Prune and How Much

Pruning is generally limited to removing spent flower stalks and any dead or yellowing leaves from the base of the rosette to maintain plant health and appearance.

  • Remove spent flower stalks
  • Tidy dead or yellowing foliage
  • Avoid cutting into the crown

Use fine-pointed tools for precise removal, taking care not to damage the inner growth of the rosette.

How to Grow Silky Mountain Daisy

Cultivating Silky Mountain Daisy ( Celmisia holosericea ) is a rewarding endeavor for any gardener interested in New Zealand's unique flora. This species can be propagated through several methods, each requiring specific conditions to ensure healthy growth and establishment. Successful propagation depends on mimicking the plant's natural environment and providing consistent care during the early stages of development.

From Seed

Propagation from seed is often the most effective way to produce a large number of Silky Mountain Daisy plants. Seeds should be collected when they are fully mature. Freshly collected seeds generally have higher germination rates than those that have been stored for long periods.

Propagation from fresh seed is possible but can be challenging. Seeds require shade and consistent moisture to germinate.

  1. Sow fresh seeds thinly on a moist, gritty seed-raising mix.
  2. Keep in a shaded, cool, and consistently moist environment.
  3. Germination can be slow and irregular.
  4. Grow seedlings on carefully in individual pots.

Patience is required, and maintaining stable, cool, moist conditions is key for successful seed germination.

From Cuttings

For those wishing to replicate specific characteristics of a parent plant, vegetative propagation via cuttings is the preferred method. This technique ensures that the new plants are genetically identical to the source. Semi-hardwood cuttings taken during the appropriate season usually yield the best results for this species.

Softwood or semi-hardwood cuttings can be attempted, ideally in late spring or early summer.

  1. Take small, healthy cuttings (5-7cm).
  2. Dip in rooting hormone powder.
  3. Insert into a free-draining, humid propagation mix.
  4. Provide bottom heat and consistent humidity.

Additional Methods

Depending on the growth habit of Silky Mountain Daisy, other methods such as division or layering might also be viable options. Division is particularly suitable for plants that form dense clumps or have spreading root systems, while layering can be used for species with trailing or flexible stems.

Division of established clumps can be done carefully in early spring, but this plant is slow to establish new divisions.

  1. Gently lift a mature clump.
  2. Divide carefully into sections with roots.
  3. Replant immediately into well-prepared soil.

Pests & Diseases

Generally robust. The main issues are usually related to poor drainage leading to root and crown rot. Slugs and snails can sometimes target young growth. Ensure good air circulation and well-drained soil to minimize problems.

Cultural Significance

Celmisia species are iconic elements of New Zealand's alpine flora, symbolizing the pristine beauty and unique biodiversity of the high country.

  • Iconic alpine species
  • Valued for its unique beauty
  • Endemic to the South Island

Bonus Tip

To best display its silvery foliage, plant Celmisia holosericea against darker green plants or in a crevice garden where its texture can be appreciated up close.

Plant Conservation

Celmisia holosericea is currently classified as "Not Threatened" under the New Zealand Threat Classification System. It is relatively widespread in Fiordland, its primary stronghold. However, like all alpine species, it faces ongoing threats from habitat disturbance, climate change impacting snowmelt patterns, and the potential spread of invasive species into its ecosystems. Careful management of its habitats is crucial for its long-term security.