Small Cushion Daisy
Abrotanella pusilla
Abrotanella pusilla is the smallest of New Zealand's cushion daisies, forming miniature mounds that rarely exceed 10 centimeters across even after decades of growth. This remarkable alpine specialist is endemic to the South Island's highest mountains, particularly in the Southern Alps, Fiordland, and the mountains of Northwest Nelson. Found primarily above 1600 meters elevation, it often grows higher than any other flowering plant in its range, surviving in the most extreme fellfields and rock crevices up to 2400 meters. The species epitomizes the miniaturization strategy of alpine adaptation - by remaining incredibly small and compact, it minimizes exposure to devastating winds while maximizing heat retention. Despite its tiny size, individual plants may be extremely old, with some cushions estimated at over 50 years. This patient survivor belongs to an elite group of New Zealand's most specialized alpine plants , adapted to conditions that would quickly kill most other species.
Plant Description
Abrotanella pusilla represents the extreme end of alpine dwarfism, with entire plants often smaller than a ten-cent coin. The cushions are extraordinarily dense and compact, typically only 5-20 millimeters tall, spreading slowly to form tight mounds rarely exceeding 10 centimeters diameter. Individual shoots are so tightly packed that the cushion surface appears almost continuous, resembling a green pebble more than a conventional plant.
The leaves are the smallest in the genus, typically just 1-3 millimeters long and less than 0.5 millimeters wide, densely imbricate and appressed to the stem. They are thick and somewhat fleshy, with a pronounced keel and minutely hairy margins. This extreme reduction in leaf size minimizes surface area exposed to desiccating winds while the thick cuticle and dense pubescence provide additional protection against water loss and UV radiation.
Flowering, when it occurs, is easily overlooked even by careful observers. The minute capitula, only 2-3 millimeters diameter, sit embedded within the cushion surface. They lack ray florets entirely, consisting of just a few disc florets that are pale yellow to almost white. The species appears to flower irregularly, perhaps only in favorable years, and seed production is correspondingly sporadic. This reproductive strategy - investing primarily in persistence rather than reproduction - is common among extreme alpine plants where seedling establishment is exceptionally rare.
Quick Facts
| Scientific Name | Abrotanella pusilla |
|---|---|
| Height | 1-3 cm |
| Family | Asteraceae |
| Form | Tiny, tight cushion; 0.5-2 cm tall |
| Light | Full sun; exposed sites |
| Soil | Very free-draining, gritty mineral mix |
| Hardiness | Cold hardy if kept dry in winter |
| Water Needs | Low to moderate |
| Spread | 30-60 cm |
| Frost Tolerance | High - tolerant of severe freezes |
| Salt Tolerance | Low to moderate |
| Growth Rate | Fast |
| Lifespan | Annual |
Climate Best Suited to
Best in cool-summer climates with strong airflow and sharp drainage. In warmer districts, grow in a raised trough or alpine house.
Regional Suitability
| City | Climate Suitability |
|---|---|
| Queenstown | Ideal |
| Wānaka | Ideal |
| Twizel | Ideal |
| Christchurch | Moderate |
| Wellington | Moderate |
| Auckland | Marginal |
| Dunedin | Excellent |
| Hamilton | Challenging - requires cool conditions |
| Tauranga | Challenging - requires cool conditions |
| Napier | Challenging - requires cool conditions |
| Palmerston North | Good |
| Nelson | Good |
| Invercargill | Excellent |
| New Plymouth | Challenging - requires cool conditions |
| Rotorua | Challenging - requires cool conditions |
| Whangarei | Challenging - requires cool conditions |
| Whangārei | Suitable |
| Gisborne | Suitable |
| Whanganui | Suitable |
Plant Habitat
Abrotanella pusilla occupies the most extreme habitats available to flowering plants in New Zealand, growing in sites where even other cushion plants struggle to survive. It specializes in the highest, most exposed fellfields, summit plateaus, and rock crevices where snow-free conditions alternate with extreme cold. These sites experience the full force of alpine weather, with winds regularly exceeding 200 km/h and temperature fluctuations of 40°C or more within a single day.
The species shows strong substrate preferences, most commonly occurring on stable, fine-textured substrates derived from schist, argillite, or highly weathered greywacke. It avoids coarse, unstable screes and areas with prolonged snow cover. The microscale topography is crucial - plants typically establish in small depressions or crevices that provide minimal shelter while still maintaining the excellent drainage essential for survival.
Soil development is minimal in these extreme sites. The substrate typically consists of 95% or more mineral particles with organic matter content below 0.5%. Despite this apparent sterility, these soils are often rich in essential minerals released by ongoing weathering. The pH typically ranges from 5.5 to 6.5, though the species tolerates broader ranges where other factors are favorable.
Associated species are few, reflecting the extreme conditions. Where present, companions may include Raoulia bryoides , Haastia pulvinaris , and highly reduced forms of Dracophyllum muscoides . More often, A. pusilla grows in pure stands or as isolated cushions in otherwise barren fellfield.
Plant Conservation
Although not currently threatened, Abrotanella pusilla is naturally rare due to its extremely specialized habitat requirements. Climate change poses a significant long-term threat as the species already occupies many of the highest available sites in its range. Unlike species at lower elevations that can migrate upward, A. pusilla has literally nowhere higher to go on many mountains.
Recent studies have documented concerning changes in high alpine plant communities. Warmer temperatures are enabling more competitive species to establish at increasingly high elevations. Grasses and herbs that were previously excluded by extreme cold are now found growing among cushion plant communities, potentially outcompeting these slow-growing specialists. Additionally, changes in the timing and duration of snow cover disrupt the environmental cues these plants rely on for their annual cycles.
Direct human impacts are generally limited due to the remote, inhospitable nature of the habitat. However, increasing mountaineering and photography tourism has led to localized trampling damage. The growing popularity of peak-bagging has resulted in informal trails across previously undisturbed cushionfields. Even minimal disturbance can be catastrophic - a single footstep can destroy a cushion that took decades to establish, with no prospect of recovery within human timescales.
Growing Requirements
Soil Requirements
Use a lean, mineral, fast-draining crevice mix: coarse sand, grit and fine gravel; minimal organics.
- Crevice or trough setting
- Fine grit top-dress around the crown
Light Requirements
Full sun with good airflow; light afternoon shade in hot summers.
Water Requirements
Light, infrequent watering; keep almost dry in winter.
Planting Guide
Best Planting Practices
Set shallowly into a narrow crevice; spread roots along the slit; firm with gritty mix and finish with grit mulch. Successful establishment requires careful attention to site preparation, timing, and ongoing care. Consider local climate conditions and soil characteristics when selecting planting locations. Regular monitoring during establishment ensures the best outcomes for long-term plant health and development.
Ecological Role
Environmental Benefits
Despite its minute size, Abrotanella pusilla functions as a keystone species in the highest alpine environments. Each tiny cushion creates a microhabitat with significantly moderated environmental conditions. Temperature measurements show that cushion interiors can be 10-15°C warmer than ambient air during sunny periods, while remaining several degrees warmer at night. This thermal oasis supports a specialized community of micro-arthropods, including endemic springtails and mites found nowhere else.
The cushions play a crucial role in the initial stages of soil formation in these extreme environments. By trapping wind-blown particles and contributing organic matter through slow decomposition of old leaves, they create tiny pockets of developed soil in otherwise sterile substrates. These enriched microsites may eventually allow establishment of other alpine plants, initiating slow successional processes that unfold over centuries.
Research has revealed fascinating interactions between cushion plants and the surrounding physical environment. The cushions modify wind patterns at a microscale, creating eddies that deposit fine particles and seeds preferentially around their margins. This process, termed 'ecological engineering,' gradually transforms barren fellfields into more complex communities, though the timescales involved span multiple human generations.
Uses & Significance
Garden Uses
For specialist alpine troughs and crevice gardens; valued for extreme miniaturisation and texture. Traditional and contemporary uses reflect both cultural significance and practical applications in modern horticulture and conservation. Understanding these various uses helps appreciate the full value of the species beyond its ornamental qualities.
- Alpine trough collections
- Rock crevice plantings
- Miniature landscapes
Landscaping Uses
Garden Design Applications
Excellent for rock gardens, alpine collections, and naturalistic plantings. Best used in open, well-drained positions where its distinctive form can be appreciated. Combines well with other native alpine plants and provides year-round structure. Consider placement carefully due to sharp foliage - avoid high-traffic areas. Creates dramatic focal points in contemporary and native-themed garden designs.
Seasonal Care
Spring
Check winter losses; resume light feeding.
Summer
Water lightly in prolonged dry spells; ensure airflow.
Autumn
Reduce watering; tidy grit; confirm drainage.
Winter
Keep nearly dry; avoid cold, stagnant wet.
Pruning
Pruning Techniques
Pruning is generally not required for this diminutive alpine creeper, which grows too slowly to ever become unruly. Maintenance should focus on keeping the mat free of debris and potentially checking the creeping stems for firm rooting into the substrate. If the plant becomes too extensive in a small trough, the creeping runners can be snipped back with fine scissors. Dead flower heads are tiny and unobtrusive, so deadheading is not necessary for aesthetics.
How to Grow Small Cushion Daisy
From Seed
Propagating Abrotanella pusilla from seed requires exceptional patience and specific conditions rarely achieved in cultivation. Seeds must be collected at exactly the right moment - too early and they're not viable, too late and they've dispersed. The collection window may be just days in late summer. Fresh seed is essential as viability drops to near zero within two months of collection.
Sow immediately on a mix of 60% sand, 30% fine pumice, and 10% sieved moss peat. Seeds require light for germination so surface sow only, misting gently to settle. Cold stratification at 1-3°C for 8-10 weeks improves germination. Maintain at 5-10°C during germination, which may take 3-6 months. Even under ideal conditions, germination rates rarely exceed 30%.
Growth is extraordinarily slow - seedlings may be just 2mm across after their first year. Maintain in original containers for at least 3 years before attempting to transplant. Success rates from seed to established plant are typically below 20%, making this species one of the most challenging New Zealand natives to propagate.
From Division
Division is theoretically possible but practically inadvisable. The minute size and extremely slow growth rate mean that even 'mature' cushions of 5-10cm diameter may have taken 30+ years to develop. Any division would set back both portions significantly, likely resulting in the death of both. This method should be considered only as a last resort to preserve unique genetic material.
Advanced Techniques
Advanced propagation techniques include tissue culture for conservation purposes and specialized mycorrhizal inoculation to improve establishment success. Research into optimal hormone treatments and environmental triggers continues to improve propagation rates. Commercial nurseries are developing improved protocols for mass production while maintaining genetic diversity. Understanding these methods helps both commercial growers and dedicated enthusiasts achieve better results with challenging species.
Troubleshooting Common Issues
Poor germination often results from old seed or inadequate stratification. Seedling losses typically indicate overwatering or insufficient drainage. Slow establishment may suggest inappropriate soil conditions or excessive heat stress. Yellowing foliage usually indicates nutrient deficiency or waterlogged conditions. Regular monitoring and prompt intervention prevent minor issues from becoming major problems affecting long-term plant health and garden performance.
Pests & Diseases
In its natural habitat, Abrotanella pusilla experiences few pest or disease problems, protected by the extreme conditions that exclude most organisms. The primary natural threat is physical damage from frost heave, wind abrasion, and rockfall rather than biological factors.
In cultivation, the species is extremely susceptible to fungal pathogens that are absent from its alpine habitat. Crown rot caused by various water molds can kill plants within days if drainage is imperfect. The tiny size makes early detection difficult - by the time symptoms are visible, it's usually too late. Prevention through meticulous attention to drainage and air circulation is the only reliable approach.
Perhaps the greatest 'pest' in cultivation is the grower's temptation to provide too much care. These plants are adapted to extreme neglect - regular watering, feeding, or repotting that would benefit most plants will quickly kill A. pusilla . Success requires mimicking the harsh conditions of the alpine fellfield as closely as possible.
Cultural Significance
Traditional Uses and Values
Small Cushion Daisy represents the remarkable adaptation of New Zealand's alpine flora to extreme environments. While not specifically used by Māori due to its remote high-altitude habitat, these cushion plants embody the resilience and specialized evolution found throughout New Zealand's mountain ecosystems. They serve as indicators of pristine alpine environments and are valued by botanists and conservationists as examples of unique island biogeography. For modern New Zealanders, these plants symbolize the fragile beauty of our alpine heritage and the importance of protecting high-country ecosystems from climate change and human impact.
Bonus Tip
The specific epithet 'pusilla' translates to 'very small' or 'insignificant', aptly describing this minute plant. Its slender, creeping stems can root as they spread, allowing it to slowly colonize moist alpine soils and form loose, tufted mats that help stabilize fine substrates in its harsh native environment.
