Large Mountain Daisy
Celmisia semicordata
The Large Mountain Daisy (scientific name: Celmisia semicordata ), also known by its Māori name Tikumu, is one of New Zealand's most iconic and robust alpine herbs. Endemic to the South Island, it is instantly recognizable by its massive rosettes of leathery, sword-shaped leaves that shimmer with a brilliant silver-green hue. This spectacular plant is a master of survival, thriving in the challenging environments of the Southern Alps, from sea-level bluffs to high alpine herbfields. This comprehensive guide explores its unique characteristics, cultural history, and specific requirements for those wishing to bring a piece of the New Zealand high country into Alpine Plants .
Plant Description
Celmisia semicordata is a bold, perennial herb that forms impressive, tightly packed rosettes or large clumps. Its most defining characteristic is its foliage; the leaves are thick, leathery, and sword-shaped, reaching lengths of 30 to 60 centimetres and widths of 4 to 10 centimetres. The upper surface of the leaf is covered in a beautiful silvery or silver-green pellicle that reflects intense mountain light, while the underside is protected by a dense mat of soft white hairs (tomentum). In summer, typically from December to January, the plant produces large, singular daisy-like flowers on stout, hairy stems that can reach up to 50 centimetres tall. These blooms are 4 to 10 centimetres in diameter, featuring pure white ray florets surrounding a bright yellow central disc. The plant creates a dramatic architectural statement in the landscape, with individual rosettes merging over time to form significant silvery colonies.
Quick Facts
| Scientific Name | Celmisia semicordata |
|---|---|
| Height | 30-60 centimetres |
| Spread | 40-80 centimetres |
| Water Needs | Moderate (Moist but well-drained) |
| Light | Full Sun to Partial Shade |
| Frost Tolerance | High (-10°C) |
| Salt Tolerance | Moderate to High |
| Growth Rate | Slow to Medium |
| Lifespan | Long-lived perennial |
Climate Best Suited to
Tikumu is perfectly adapted to cool, moist climates. It thrives in regions with significant rainfall and high humidity, characteristic of the western and central South Island. While it can tolerate intense sunlight at high altitudes where the air is cool, it struggles in the combined heat and humidity of lowland northern New Zealand. It is fully frost-hardy and expects a cold winter. In gardens outside of its natural mountain range, it requires a position that stays cool and has excellent air movement to prevent rot and heat stress.
Regional Suitability
| City | Climate Suitability |
|---|---|
| Auckland | Poor (Too warm and humid) |
| Wellington | Moderate (Requires a cool, breezy spot) |
| Christchurch | Good (In specialized alpine spots) |
| Dunedin | Excellent |
| Queenstown | Excellent |
Plant Habitat
Celmisia semicordata is found throughout the South Island of New Zealand, occupying a surprisingly wide range of elevations. While most abundant in subalpine and lower alpine grasslands and herbfields (typically between 600 and 1400 metres), it can also be found on steep coastal bluffs at sea level. It is a frequent inhabitant of snow-tussock grasslands and open subalpine scrub. This species is notably opportunistic and will rapidly colonize mountain sites that have been disturbed by burning, erosion, or heavy grazing, where it forms dense, silver carpets.
Plant Conservation
The Large Mountain Daisy is currently classified as "Not Threatened." It is one of the most common and widespread Celmisia species in the South Island. Because it is unpalatable to most livestock and can thrive in disturbed ground, it has remained resilient even in areas modified by human activity. However, local populations can be affected by intensive farming or large-scale habitat loss. Most of its primary habitat is safely contained within New Zealand's national park system, ensuring its long-term survival.
Growing Requirements
Soil Requirements
Needs deep, cool, and humus-rich soil that mimics the organic-rich debris of alpine herbfields.
- Moist but perfectly drained
- Slightly acidic to neutral pH
- High mineral and grit content
Light Requirements
Requires high light levels to maintain its silvery pellicle. Full sun is best if roots stay cool.
- Full sun in cool climates
- Dappled shade in warmer areas
- Avoid hot, enclosed courtyards
Water Requirements
Consistent moisture is vital. It does not tolerate prolonged dry periods or "wet feet."
- Regular deep watering
- Good air circulation is essential
- Dislikes excessive winter wet
Planting Guide
Choose a spot in a rock garden, raised bed, or alpine trough that remains cool. Dig a deep hole and incorporate plenty of leaf mold and grit. When planting Tikumu, it is crucial to ensure the crown of the plant is slightly elevated above the soil surface. Surround the base with a thick mulch of grey schist chips or clean gravel; this prevents the lower leaves from rotting on damp soil and reflects light up into the plant. If you are planting in a warmer region, position the plant where it will receive morning sun but be protected from the intense heat of the afternoon.
Ecological Role
As a dominant member of many alpine communities, Celmisia semicordata plays a key role in stabilizing high-altitude soils. Its dense rosettes act as a protective layer, reducing erosion from wind and snow melt. The flowers are a significant nectar resource for specialized alpine insects, including native moths, flies, and bees. Furthermore, the discarded outer leaves of the rosettes accumulate at the base, slowly breaking down to create tiny pockets of nutrient-rich soil in an otherwise mineral-heavy landscape, supporting a wider diversity of mountain flora.
Uses & Significance
Garden Uses
A premier specimen for specialized alpine gardens and dramatic architectural plantings.
- Stunning silver texture contrast
- Bold focal point in rockeries
- Architectural container plant
Tikumu holds a special place in Māori culture, particularly for South Island iwi.
- Māori name is Tikumu
- Leaves were used traditionally for making rain-capes
- Silvery down was used as a wound dressing
Ecological Value
Contributes to the health and stability of New Zealand's subalpine ecosystems.
- Important nectar source for mountain insects
- Stabilizes fragile alpine soils
- Supports a community of high-altitude invertebrates
Cultural Significance
While specific records are limited for this species, Celmisia semicordata sits within a wider native plant tradition valued for its ecological role and local stewardship.
Landscaping Uses
In landscaping, the Large Mountain Daisy is used to create moments of intense visual interest. Its brilliant silver foliage provides a striking contrast to the dark greens of native shrubs or the deep reds of Horopito (Pseudowintera). It is often used in mass plantings to create a "river" of silver through a rockery or tucked into the crevices of large landscape boulders. Because of its large size and bold texture, it works well as an architectural centerpiece in specialized alpine-themed landscapes or in large, well-drained troughs.
Seasonal Care Calendar
Spring
As growth resumes, focus on root health and tidiness.
- Clear away winter debris from rosettes
- Apply a light dose of organic fertiliser
- Check drainage after winter rains
Summer
The peak growing and flowering period.
- Ensure consistent moisture in root zone
- Enjoy the large white daisy flowers
- Watch for overheating in lowland sites
Autumn
Flowering ends and the plant prepares for winter.
- Collect fresh seeds for propagation
- Reduce watering as dormancy nears
- Ensure mulch layer is clean and tidy
Winter
The plant enters its dormant phase.
- Protect from excessive winter wetness
- Ensure good air circulation around base
- Fully frost hardy; no protection needed
When to Prune and How Much
Celmisia semicordata requires minimal pruning, but grooming is essential for its health.
- Remove brown or dead leaves from the base of the rosette
- Cut back flower stems at the base once they have finished
- Gently clear away any organic debris caught in the crown
Always use sterilized snips. Grooming is best done in late winter or early spring before the new season's growth starts. The main goal is to prevent moisture from being trapped by dead leaves, which is the most common cause of fungal rot in this species.
How to Grow Large Mountain Daisy (Tikumu)
Growing the Large Mountain Daisy ( Celmisia semicordata ) is a journey that requires patience and a bit of "mountain magic." Success hinges on providing a cool, free-draining environment. In its natural home, its roots are constantly bathed in cool, oxygenated mountain water, while its leaves are exposed to bright, clear light. Replicating this in a garden means using a gritty, mineral-heavy soil mix and ensuring excellent air movement. Disliking stagnant air and humidity, Tikumu thrives in open, breezy spots. Traditionally, some gardeners recommend adding a few handfuls of well-rinsed seaweed to the soil to provide the trace elements the plant enjoys. Be vigilant; this species can be prone to "sudden death" if the conditions are not just right, often due to a hidden fungal rot in the crown. It is a challenging but deeply rewarding plant for any New Zealand garden enthusiast.
From Seed
Seeds should be sown as fresh as possible for the best results.
- Collect ripe seeds in late summer when the heads are dry.
- Sow on the surface of a gritty, well-drained seed mix.
- Seeds require light to germinate; do not bury them deeply.
- Apply cold stratification (3-4 weeks in the fridge) to mimic winter.
Keep the tray in a cool, bright spot and maintain even moisture.
From Cuttings
Offsets or individual rosettes can be rooted in spring.
- Identify a side rosette that has a short section of stem.
- Carefully remove it from the parent plant using a sharp blade.
- Insert into a mix of pure sand or fine grit.
- Keep in a cool, humid environment until roots form.
Additional Methods
Division of large clumps is possible but must be done with great care.
- Gently separate a section of the clump in early spring.
- Ensure each piece has its own established root system.
- Replant immediately and protect from direct sun until established.
General Propagation Tips (Seeds & Cuttings)
Successful propagation of native New Zealand plants requires attention to detail and patience. When growing from seed, it is essential to start with fresh, viable seeds collected when they are fully mature. Clean the seeds thoroughly to remove any fleshy pulp, which can inhibit germination. Sow the seeds on the surface of a seed-raising mix that is free-draining yet moisture-retentive. A mix of peat and coarse sand or perlite often works well. Cover the seeds lightly with a fine layer of grit or sieved potting mix, or leave them uncovered if they require light to germinate. Keep the trays in a sheltered, shaded spot and maintain consistent humidity; a plastic cover can help but ensure there is adequate ventilation to prevent fungal diseases. Germination can be erratic, sometimes taking several months, so do not discard the trays too early. For vegetative propagation, semi-hardwood cuttings are often the most successful method for shrubby species. Take cuttings in late summer or early autumn, selecting healthy, non-flowering shoots. Trim them to about 10-15 cm in length, making a clean cut just below a node. Remove the lower leaves and dip the cut end in rooting hormone to encourage root development. Insert the cuttings into a propagating mix, ensuring they are firm and stable. Place them in a humid environment, such as a mist unit or a covered frame, out of direct sunlight. Rooting can take anywhere from a few weeks to several months. Once roots have formed, pot the young plants into individual containers and harden them off gradually before planting out. Division is another effective method for clump-forming plants like sedges, grasses, and lilies. This is best done in autumn or early spring when the plant is actively growing. Lift the clump carefully and tease the roots apart, using two garden forks or a sharp knife if the clump is dense. Ensure each division has a good root system and healthy shoots. Replant the divisions immediately, watering them well to settle the soil around the roots. With proper care, these new plants will establish quickly and grow into healthy specimens. By employing these methods, you can successfully expand your collection of native flora and contribute to the preservation of New Zealand's unique botanical heritage.
Pests & Diseases
The primary threat to Tikumu in cultivation is fungal rot, specifically Phytophthora or similar rots that affect the crown and roots. This is almost always caused by poor drainage, stagnant air, or excessive heat. Slugs and snails find the fleshy leaves irresistible, so regular monitoring is necessary. Aphids can sometimes cluster on the flower buds in early summer. If the plant looks stunted, check the roots for root mealybug, which can be an issue in container-grown alpine plants.
Bonus Tip
For the best silver foliage, ensure your plant gets plenty of bright light and clear air. The silver "pellicle" on the leaves is actually a protection against intense mountain radiation-the more light it gets (as long as it's not hot), the more silvery and spectacular the leaves will become.
