Colenso's Mingimingi
Acrothamnus colensoi
A compact alpine-subalpine heath shrub (Ericaceae) with small, leathery leaves and bell-like flowers that may give way to small berries. It inhabits open, cool, free-draining habitats in high country shrublands and rocky margins. In cultivation, it prefers cool summers, high light and excellent drainage. shrubs .
Plant Description
A dense, finely branched shrub to subshrub. Leaves small, often coriaceous, with entire to toothed margins depending on form. Bell-shaped flowers are produced in clusters; fruits may be small berries typical of allied genera. The compact habit and small leaves reduce moisture loss and resist alpine winds.
Quick Facts
| Scientific Name | Acrothamnus colensoi |
|---|---|
| Family | Ericaceae |
| Form | Compact alpine-subalpine heath shrub |
| Light | Full sun to high bright light |
| Soil | Free-draining, slightly acidic, low-organic mineral mix |
| Tolerance | Wind, cold; dislikes stagnant humidity and heat |
| Height | 0.3-2 m (compact shrub) |
| Spread | 40-120 cm across |
| Water Needs | Low to moderate; free-draining soils |
| Frost Tolerance | High - tolerant of severe freezes |
| Salt Tolerance | Low to moderate |
| Growth Rate | Fast |
| Lifespan | Long-lived perennial |
Climate Best Suited to
Cool-summer districts with strong airflow and rapid drainage; excels in alpine troughs and rock gardens.
Regional Suitability
| City | Climate Suitability |
|---|---|
| Queenstown | Ideal |
| Wānaka | Ideal |
| Christchurch | Ideal |
| Wellington | Moderate |
| Auckland | Marginal |
| Whangārei | Suitable |
| Hamilton | Suitable |
| Tauranga | Suitable |
| Rotorua | Suitable |
| Gisborne | Suitable |
| New Plymouth | Suitable |
| Napier | Suitable |
| Whanganui | Suitable |
| Palmerston North | Suitable |
| Nelson | Suitable |
| Dunedin | Suitable |
| Invercargill | Suitable |
Plant Habitat
Acrothamnus colensoi occurs in natural habitats characteristic of Aotearoa, forming part of distinctive plant communities where site stress and local disturbance shape vegetation patterns. It favours exposed slopes, screes or fellfields with thin, rapidly drained mineral soils, enduring intense radiation, wind and freeze-thaw cycles. On the coast it occupies sunny, wind‑prone sites with sandy or rocky substrates, where salt‑laden air and periodic drought limit competition. These preferences explain its patchy distribution and sensitivity to changes in hydrology, competition and disturbance regimes.
Plant Conservation
Populations of Acrothamnus colensoi are influenced by land use, browsing and weeds. Protecting intact habitat mosaics, reducing browser pressure, and managing invasive plants sustain recruitment. Where local stands are small or isolated, eco‑sourced augmentation and careful site stewardship help secure long‑term viability.
Growing Requirements
Soil
Slightly acidic, gritty, free-draining mix; avoid heavy, water-retentive composts.
Light
Full sun in cool climates; light afternoon shade where summers are hot.
Water
Moderate; keep evenly moist but never waterlogged; reduce in winter.
Planting Guide
Planting Steps
Plant in the cool, moist months into weed‑free ground. Set plants slightly proud of the surrounding soil, water to settle, and mulch with coarse gravel or woodchips while keeping the stem base clear. Grouping two to three plants replicates natural patterns and improves establishment under local conditions.
Ecological Role
Fauna Support
Acrothamnus colensoi contributes structure and seasonal resources where it grows, providing cover and habitat for invertebrates and, when flowering or fruiting, nectar, pollen or seed for fauna.
Environmental Stabilisation
By tolerating the stresses of its environment, it helps stabilise sites and enrich small‑scale habitat diversity.
Uses
Traditional and Modern Applications
Ideal for rock and gravel gardens that emulate alpine processes, or for specialised collections. Suited to sunny, maritime gardens with sandy or rocky soils where wind and salt are considerations.
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
Year-Round Maintenance
Spring management focuses on removing winter-damaged foliage and assessing drainage. Summer care emphasizes maintaining adequate moisture without waterlogging. Autumn preparation includes reducing irrigation and ensuring good air circulation. Winter protection may require covering in areas subject to excessive moisture. Year-round monitoring ensures early detection of problems and maintenance of optimal growing conditions.
Pruning
Pruning Techniques
Little pruning is required; remove dead or crossing material after flowering and avoid hard renovation cuts. Light tip‑pruning maintains compact form without compromising the plant’s natural character.
How to Grow Colenso's Mingimingi
From Seed
Propagation of Acrothamnus colensoi from seed is challenging and requires patience. The seeds are enclosed in a fleshy fruit which must be cleaned off before sowing. Mash the berries gently in water and decant the pulp.
Sow the cleaned seed on the surface of a seed mix containing peat and sand. Cover very lightly. Germination is notoriously slow and can take anywhere from 3 to 18 months. Some growers suggest subjecting the seed tray to natural seasonal temperature fluctuations to break dormancy.
Keep the tray in a shady, consistent environment. Do not let it dry out. Once seedlings appear, they are slow to develop and should be left undisturbed until they are robust enough to handle.
From Cuttings
Semi-hardwood cuttings taken in late summer or early autumn offer a viable alternative to seed. Select healthy, non-flowering tips about 5-8cm long.
Remove the lower leaves carefully to avoid tearing the bark. Dip the cut end in a rooting hormone gel or powder. Insert the cuttings into a mix of sand, perlite, and peat. High humidity is beneficial, so placing the pot in a propagator or plastic bag can help.
Rooting is slow, often taking several months. Check for resistance before attempting to repot.
Cultivation Notes
Colenso's Mingimingi requires specific conditions to thrive. It prefers a cool, acidic, free-draining soil rich in organic matter, similar to the peat and grit of its native subalpine heathland.
It dislikes high humidity and stagnant heat. In warmer lowland gardens, a cool semi-shaded spot is best. In cooler districts, it tolerates more sun. Excellent drainage is essential to prevent root rot.
Pests & Diseases
Good siting prevents most problems-sharp drainage and appropriate exposure are key. Crown and root rots arise if winter wet persists; keep crowns elevated and water moving. Protect young plants from browsing where deer, goats or rabbits are present.
Cultural Significance
Traditional Uses and Values
While no specific traditional uses are recorded for this species, it is named after William Colenso, one of New Zealand's most prolific early botanists and explorers. As a widespread component of alpine scrub, it represents the characteristic 'mingimingi' vegetation that covers much of the high country, playing a vital role in stabilizing mountain slopes and supporting native biodiversity.
Bonus Tip
Alpine Jewel
This subalpine shrub produces attractive pink or red berries in autumn which provide a splash of colour against its needle-like foliage. It is a fantastic subject for a rock garden or trough where these delicate details can be closely observed.
