1. Introduction

Habitat and Distribution, Native Continent

Hedyscepe canterburyana is endemic exclusively to Lord Howe Island, a small volcanic remnant located 600 kilometers east of mainland Australia in the Tasman Sea. This critically endangered palm has one of the most restricted natural distributions of any palm species, confined to the mist forests on the upper slopes and summit plateaus of Mount Gower (875m) and Mount Lidgbird (777m). The entire wild population exists above 400 meters elevation in an area of less than 5 square kilometers. The species inhabits perpetually humid cloud forests where it grows in deep volcanic soils enriched by continuous leaf litter decomposition, thriving in the almost constant mist and frequent rainfall that characterizes these mountain summits.

Native range: Lord Howe Island cloud forests, 600km east of Australia
Click on markers for details

Taxonomic Classification and Scientific Classification

Synonyms

• Kentia canterburyana C.Moore & F.Muell. (basionym)
• Hedyscepe canterburyana var. glabrescens F.Muell. ex Drude
• Veitchia canterburyana (C.Moore & F.Muell.) H.Wendl.

Common Names

• Big Mountain Palm (English)
• Canterbury Palm (English)
• Lord Howe Island Big Mountain Palm (English)
• Umbrella Palm (local Lord Howe Island name)
• Mountain Thatch Palm (historical)

Expansion of This Palm in the World

Limited but significant cultivation globally:

• Major botanical gardens worldwide (Kew, Fairchild, Sydney)
• Private collections in Australia, California, Hawaii
• European palm collections (Mediterranean coast)
• Conservation programs in Australia and New Zealand
• Increasingly available through specialist nurseries
• Popular with serious palm collectors
• CITES Appendix II listed species

2. Biology and Physiology

Morphology

Stem

Solitary, robust trunk reaching 10-15 meters in habitat (usually shorter in cultivation), with a diameter of 15-25 cm. The trunk is smooth, pale gray to light brown, marked with closely spaced ring scars. Unlike its relative Howea, the trunk is noticeably swollen at the base, tapering gradually upward. The crown shaft is prominent, 60-100 cm long, bright green to yellowish-green, formed by tightly clasping leaf bases. Young plants develop a distinctive bulbous base before trunk elongation begins.

Leaves

Pinnate leaves of exceptional beauty, 2-3 meters long, strongly recurved to create an umbrella-like crown that gives the palm its distinctive silhouette. Pinnae are regularly arranged, 60-80 per side, dark green above and silvery-green below, held in a single plane. The rachis has a characteristic twist that orients all pinnae downward. New leaves emerge bright red to bronze, creating a striking contrast. The crown typically holds 8-14 leaves, fewer than most palms of similar size.

Flower Systems

Inflorescences emerge below the crownshaft, 60-120 cm long, branched to one order. The palm is monoecious with flowers arranged in triads (two male, one female) near the branch bases, and pairs or single male flowers toward the tips. Male flowers are cream to pale yellow with 30-60 stamens. Female flowers are green, larger than males. Flowering occurs irregularly, often triggered by environmental stress. Fruits are large for the subfamily, ovoid to ellipsoid, 4-6 cm long, ripening from green through red to dark purple or black.

Life Cycle

• Germination: 6-18 months (highly variable)
• Seedling stage: 3-5 years
• Juvenile: 8-12 years developing trunk
• Crown shaft formation: 10-15 years
• Reproductive maturity: 15-25 years
• Lifespan: 100-150+ years estimated

Specific Adaptations to Different Climate Conditions

• Cloud forest adaptation: Specialized for perpetual humidity
• Wind resistance: Flexible leaves and strong trunk
• Low light tolerance: Thrives in misty, filtered light
• Cool temperature preference: Adapted to mountain climate
• Nutrient cycling: Efficient at capturing nutrients from fog drip
• Slow metabolism: Adaptation to limited resources

3. Reproduction and Propagation

Seed Reproduction

Seed Morphology and Diversity

Seeds are among the largest in the Archontophoenicinae, ellipsoid to ovoid, 25-35 mm long, 20-25 mm diameter. The endosperm is homogeneous with a lateral embryo. Fresh seeds have a fibrous mesocarp that must be removed. Seed size varies with maternal nutrition and age, with older palms producing larger seeds. The seed coat is relatively thin but hard.

Detailed Seed Collection and Viability Testing

• Collect when fruits turn deep purple-black and begin to fall
• Seeds remain viable for 3-6 months if properly stored
• Remove all fruit pulp within 24-48 hours
• Clean seeds float initially but sink after soaking
• Viable seeds are firm and heavy
• Store in slightly moist sphagnum at 15-20°C

Pre-germination Treatments

• Soak cleaned seeds for 3-5 days with daily water changes
• Scarification beneficial - file small area of seed coat
• No heat treatment needed (detrimental to cool-climate species)
• Cool stratification at 15°C for 30 days may improve uniformity
• Fungicide treatment essential due to long germination

Step-by-step Germination Techniques

1. Prepare deep containers for long radicle
2. Medium: 50% coconut coir, 30% perlite, 20% coarse sand
3. Plant seeds horizontally, half-buried
4. Maintain temperatures 20-25°C (cooler than most palms)
5. High humidity essential: 80-90%
6. Bright filtered light, no direct sun
7. Keep consistently moist but not waterlogged
8. First germination typically at 6-9 months

Germination Difficulty

Moderate to difficult. Patience required for slow, irregular germination.

Germination Time

6-18 months, with some seeds taking up to 2 years.

Seedling Care and Early Development Stages

• Maintain high humidity for first 2 years
• Growth very slow initially - first pinnate leaf at 2-3 years
• Sensitive to overfertilization when young
• Begin dilute feeding only after 6 months
• Protect from temperature extremes
• Susceptible to damping off in poor air circulation

Advanced Germination Techniques

Hormonal Treatments for Germination Enhancement

• GA3 at 100-500 ppm can improve germination rate
• Smoke water treatment shows promise
• Bottom heat to 25°C maximum (not higher)
• Hydrogen peroxide soaks may help older seeds
• Research ongoing for optimal protocols

4. Cultivation Requirements

Light Requirements

Species-specific Light Tolerance Ranges

Adapts to various light levels from 30-70% of full sunlight (600-1400 μmol/m²/s). Young plants require more shade (50-70%) while mature specimens tolerate considerable sun if humidity is adequate.

Seasonal Light Variations and Management

Can handle more light in winter and in humid coastal conditions. Interior or dry climates require more shade year-round.

Artificial Lighting for Indoor Cultivation

Bright indirect light or supplemental LED/fluorescent lighting at 600-1000 μmol/m²/s for 12-14 hours daily.

Temperature and Humidity Management

Optimal Temperature Ranges

• Ideal: 15-25°C (59-77°F)
• Summer maximum: 30°C (86°F)
• Winter minimum: 5°C (41°F)
• Best growth: 18-22°C (64-72°F)

Cold Tolerance Thresholds

Hardy to -2°C (28°F) briefly when mature. Young plants damaged below 2°C. Established plants recover from light frost damage.

Humidity Requirements and Modification Techniques

• Optimal: 70-85%
• Minimum: 50%
• Benefits from fog, mist, or coastal humidity
• Misting systems helpful in dry climates
• Grouping plants creates beneficial microclimate

Soil and Nutrition

Ideal Soil Composition and pH Values

• pH 6.0-7.0 (slightly acidic to neutral)
• Rich, well-draining mix: 30% quality compost, 30% coconut coir, 20% perlite, 10% sand, 10% charcoal
• High organic matter essential
• Volcanic soil amendments beneficial

Nutrient Requirements Through Growth Stages

• Seedlings: 20-20-20 at 1/4 strength monthly after 6 months
• Juveniles: 18-6-12 at 1/2 strength bi-weekly in growing season
• Adults: 15-5-15 plus micronutrients monthly
• Reduce feeding in cool months

Organic vs. Synthetic Fertilization Approaches

• Responds well to organic matter
• Compost tea, aged manure excellent
• Synthetic: Slow-release formulations preferred
• Avoid high salt fertilizers

Micronutrient Deficiencies and Corrections

• Magnesium deficiency common - apply Epsom salts
• Iron chlorosis in alkaline soils
• Manganese important for mountain species
• Complete micronutrient mix annually

Water Management

Irrigation Frequency and Methodology

• Consistent moisture crucial
• Water when top 2-3 cm dry
• More frequent in active growth
• Deep watering preferred
• Reduce in winter

Drought Tolerance Assessment

Low to moderate. Established plants survive brief dry periods but growth suffers.

Water Quality Considerations

Prefers soft water. Sensitive to fluoride and chlorine. Rainwater ideal.

Drainage Requirements

Essential. Cannot tolerate waterlogging despite high water needs.

5. Diseases and Pests

Common Problems in Growing

• Scale insects most serious pest
• Fungal leaf spots in poor air circulation
• Root rot in heavy soils
• Micronutrient deficiencies common

Identification of Diseases and Pests

• Scale insects: White or brown scales on leaves and rachis
• Mealybugs: In crown and leaf bases
• Fungal leaf spots: Circular brown lesions
• Phytophthora: Crown and root rot
• Spider mites: In dry conditions

Environmental and Chemical Protection Methods

• Maintain good air circulation
• Avoid overhead watering in cool weather
• Systemic insecticides for persistent scale
• Horticultural oil applications
• Copper fungicides for leaf spots
• Prevention through proper culture

6. Indoor Palm Growing

Specific Care in Housing Conditions

• Needs bright, humid location
• Benefits from summer outdoors in mild climates
• Requires space for eventual size
• Humidifier beneficial in heated homes
• Cool winter temperatures preferred
• Regular leaf cleaning important

Replanting and Wintering

• Repot young plants annually
• Mature plants every 2-3 years
• Use deep containers for taproot
• Winter: Reduce water and feeding
• Maintain above 5°C
• Increase humidity if heating used

7. Landscape and Outdoor Cultivation

Spectacular specimen palm for mild coastal and mountain climates. The umbrella-like crown creates unique architectural interest. Excellent for fog-belt gardens, coastal plantings, and highland tropical landscapes. Wind tolerance makes it suitable for exposed locations. Combines beautifully with tree ferns, other Lord Howe Island plants, and subtropical species. The red new leaves add color interest throughout the year.

Design Applications

• Cloud forest gardens
• Specimen focal points
• Conservation collections
• Botanical gardens
• Coastal fog-belt landscapes
• Highland tropical themes
• Protected courtyards
• Rare plant collections

Companion Plants

• Lord Howe Island natives: Howea forsteriana, Howea belmoreana
• Tree ferns: Cyathea, Dicksonia species
• Other palms: Archontophoenix, Rhopalostylis
• Understory plants: Ferns, bromeliads, orchids
• Shrubs: Rhododendrons, azaleas (similar requirements)

8. Cold Climate Cultivation Strategies

Cold Hardiness

USDA Hardiness Zones 9b-11. Marginal in 9a with protection.

Winter Protection

• Young plants need frost protection
• Wrap trunk in freeze cloth below 0°C
• Mulch heavily around base
• Anti-desiccant sprays reduce cold damage
• Move containers to protected areas

Hardiness Zone

Best in zones 10-11, possible in protected 9b locations

Winter Protection Systems and Materials

• Temporary greenhouse structures for young plants
• Christmas lights for minimal heat
• Frost cloth wrapping for crown
• Wind barriers crucial
• South-facing walls provide microclimate

Establishment and Maintenance in Landscapes

Planting Techniques for Success

• Choose protected site initially
• Prepare large planting hole with organic matter
• Ensure excellent drainage
• Plant at same level as in container
• Stake only if necessary
• Mulch heavily but keep from trunk
• Provide temporary shade first year

Long-term Maintenance Schedules

• Monthly: Deep watering, inspection
• Bi-monthly: Fertilization in growing season
• Quarterly: Remove old fronds, check for pests
• Annually: Top-dress with compost, micronutrient application
• Every 2-3 years: Soil amendment, major pruning