1. Introduction

Habitat and Distribution

Pritchardia mitiaroana is endemic to Makatea Island (historically known as Mitiaro in some references) in the Tuamotu Archipelago of French Polynesia, representing the only Pritchardia species naturally occurring outside of Hawaii. This extraordinary biogeographic anomaly grows on raised coral limestone (makatea) formations, primarily on the ancient reef terraces that characterize this uplifted atoll. The palm inhabits both the coastal limestone cliffs and the interior plateau at elevations from 10-70 meters above sea level.

The habitat is characterized by sharp, eroded limestone pinnacles (feo), shallow soil pockets, and exposure to salt-laden trade winds. Annual rainfall is moderate at 1,200-1,800mm with pronounced dry seasons. The species has also been introduced to a few other islands in French Polynesia for conservation purposes.

Native Continent

Scientific Classification

Synonyms

• Pritchardia vuylstekeana misapplied (not Hort.)
• Pritchardia pericularum misapplied (not Becc.)
• Long confused with other Pacific Pritchardia

Common Names

• English: Makatea fan palm, Makatea pritchardia, Tuamotu fan palm, Pacific pritchardia
• French: Palmier de Makatea, Palmier éventail de Makatea
• Horticultural trade: Makatea fan palm
• Conservation status: IUCN Red List - Endangered

Global Expansion

P. mitiaroana has limited but growing cultivation due to conservation efforts and the species' greater adaptability compared to Hawaiian Pritchardia:

• French Polynesia: Tahiti Botanical Garden (conservation collection), private gardens in Tahiti and Society Islands
• Hawaii: Hawaiian botanical gardens (few specimens)
• United States: Montgomery Botanical Center, Florida; some California private collections
• Australia: Limited cultivation in Queensland
• Europe: Rare in botanical conservatories

Seeds occasionally available from specialists. Cultivation is increasing due to conservation efforts and the species' greater adaptability compared to Hawaiian Pritchardia.

2. Biology and Physiology

Morphology

Trunk/Stem

P. mitiaroana develops a solitary, moderately robust trunk reaching 8-15 meters in height with a diameter of 20-35cm. The trunk is distinctive gray to light brown, marked with widely spaced ring scars that spiral slightly. Unlike Hawaiian species, the trunk is usually clean of persistent leaf bases except near the crown. The base shows slight swelling in mature specimens. Growth is remarkably straight despite coastal wind exposure.

Leaves

The crown is full and rounded, consisting of 25-35 large, fan-shaped leaves. Individual leaves measure 1.2-2 meters across, divided about halfway into 50-70 segments. The petiole is 1-1.5 meters long, robust, and armed with small teeth along the margins in young plants. Leaves are bright green to yellow-green above, slightly paler below with a subtle waxy coating. The segments are moderately stiff with slightly drooping tips.

Flower Systems

P. mitiaroana is hermaphroditic with impressive interfoliar inflorescences. The branched panicle reaches 1-2 meters in length, initially ascending then arching gracefully. Flowers are small (3-5mm), creamy white to pale yellow, fragrant, and produced in great abundance. The species shows some protandrous tendencies. Flowering occurs mainly during the warm season (November-March) with sporadic flowering year-round in cultivation.

Life Cycle

P. mitiaroana has a moderate life cycle of 80-150 years:

• Germination to Seedling (0-4 years): Steady early growth
• Juvenile Phase (4-15 years): Trunk initiation
• Sub-adult Phase (15-30 years): Rapid vertical growth
• Adult Phase (30-100 years): Peak reproduction
• Senescent Phase (100-150 years): Gradual decline

First flowering typically occurs at 20-30 years or when trunk reaches 4-6 meters.

Specific Adaptations to Climate Conditions

• Limestone Tolerance: Thrives in alkaline conditions (pH 7.2-8.5)
• Drought Resistance: Deep roots access limestone water reserves
• Salt Tolerance: Coastal exposure adaptation
• Wind Resistance: Flexible leaves and strong trunk
• Poor Soil Tolerance: Efficient nutrient uptake from shallow soils
• Cyclone Survival: Recovers well from crown damage

3. Reproduction and Propagation

Seed Reproduction

Seed Morphology and Diversity

P. mitiaroana produces globose to slightly ellipsoid fruits, 2.5-3.5cm diameter. Fruits are green when immature, ripening to brown or dark brown. The exocarp is smooth and relatively thick; mesocarp is fibrous and dry at maturity; endocarp is hard and thick. Seeds are spherical, 1.8-2.5cm diameter, with homogeneous endosperm. Fresh seed weight ranges from 5-12 grams. Genetic diversity is moderate despite the restricted range, suggesting a larger historical population.

Detailed Seed Collection and Viability Testing

Pre-germination Treatments

Step-by-step Germination Techniques

1. Container: Deep pots (25cm+)
2. Medium: 40% coconut coir, 30% perlite, 20% coral sand, 10% compost
3. Planting: 4cm deep
4. Temperature: 26-32°C (79-90°F)
5. Humidity: 70-80%
6. Light: Bright shade
7. Special: Alkaline water beneficial

Germination Difficulty: Easy to Moderate

Success factors:

• Fresh seeds important
• Scarification very helpful
• Warm temperatures essential
• Good drainage critical

Germination Time

• First emergence: 45-90 days
• Peak germination: 90-150 days
• Complete: within 200 days
• Success rate: 70-90% if fresh

Seedling Care and Early Development

Year 1:

• Fast initial growth
• Begin feeding at 2 months
• 60% shade adequate
• Alkaline conditions beneficial

Years 2-3:

• Rapid leaf development
• Regular fertilization
• Can reduce shade
• Wind protection important

Years 4-5:

• Trunk visible
• Nearly full sun tolerant
• Landscape ready

Advanced Germination Techniques

Hormonal Treatments for Germination Enhancement

4. Cultivation Requirements

Light Requirements

Species-specific Light Tolerance Ranges

• Seedlings (0-1 year): 600-1200 μmol/m²/s (60% shade)
• Juveniles (1-4 years): 1200-1800 μmol/m²/s (40% shade)
• Sub-adults (4-10 years): 1800-2200 μmol/m²/s (light shade to full sun)
• Adults: Full sun preferred (2200+ μmol/m²/s)

High light tolerance at all stages compared to other fan palms.

Seasonal Light Variations and Management

• Adapts well to seasonal changes
• Young plants appreciate some shade
• Adults thrive in full exposure
• More sun = better growth

Artificial Lighting for Indoor Cultivation

• High light needs
• HID or LED required
• 14-16 hours daily
• 400+ foot-candles

Temperature and Humidity Management

Optimal Temperature Ranges

• Ideal: 24-32°C (75-90°F)
• Acceptable: 18-38°C (64-100°F)
• Minimum survival: 12°C (54°F)
• Maximum tolerance: 42°C (108°F)

Heat tolerant species.

Cold Tolerance Thresholds

• Light damage: 10°C (50°F)
• Severe damage: 7°C (45°F)
• Death likely: 4°C (39°F)
• Brief cold snaps tolerated

Hardiness Zone Maps

• USDA Zones: 10a-11
• Zone 9b marginal
• Sunset Zones: 21-24, H2
• Coastal areas best

Humidity Requirements and Modification

• Optimal: 50-70%
• Minimum: 30%
• Drought adapted
• Not humidity dependent like rainforest species

Soil and Nutrition

Ideal Soil Composition and pH

Nutrient Requirements Through Growth Stages

Seedlings (0-1 year):

• Light feeding monthly
• Balanced formula
• 1/4 strength

Juveniles (1-4 years):

• NPK ratio: 3-1-2
• Monthly application
• Full strength acceptable

Adults (4+ years):

• NPK ratio: 8-3-12
• Quarterly feeding
• Supplement calcium

Organic vs. Synthetic Fertilization

Micronutrient Deficiencies and Corrections

• Magnesium: Common - dolomite lime
• Manganese: Foliar spray
• Iron: Despite alkalinity - chelated
• Boron: Occasional need

Water Management

Irrigation Frequency and Methodology

• Moderate water needs
• Deep, infrequent watering
• Drought tolerant when established
• Increase in dry season

Drought Tolerance Assessment

• Good drought tolerance
• Deep limestone water access
• Survives 2-3 months dry
• Recovery excellent

Water Quality Considerations

• Tolerates alkaline water
• Slight salt tolerance
• Hard water beneficial
• pH 7-8.5 ideal

Drainage Requirements

• Excellent drainage essential
• No waterlogging tolerance
• Raised planting helpful
• Limestone amendments improve drainage

5. Diseases and Pests

Common Problems in Growing

• Few disease issues
• Scale insects occasional
• Nutrient deficiencies if soil too acid
• Generally very healthy species

Identification of Diseases and Pests

Disease Resistance

• Remarkably disease-free in proper conditions
• Occasional leaf spots in humid conditions
• Root rot if waterlogged
• Good air circulation prevents most issues

Pest Issues

• Palm weevils: Potential threat in some regions
• Scale insects: Minor problem, easily controlled
• Mealybugs: Occasional, usually on stressed plants
• Generally pest-free compared to other palms

Environmental and Chemical Protection Methods

Prevention Primary

• Proper alkaline soil
• Good drainage
• Air circulation
• Minimal intervention needed

If Treatment Required

• Neem oil usually sufficient
• Systemic insecticides rarely needed
• Focus on cultural practices
• Very low maintenance species

6. Indoor Palm Growing

Specific Care in Housing Conditions

Indoor Challenges

• High light requirements
• Large ultimate size
• Alkalinity needs
• Better suited for outdoors in suitable climates

Container Success

• Large containers required
• Alkaline medium essential
• Bright light critical
• Regular calcium supplementation

Replanting and Wintering

Replanting Schedule

• Every 2-3 years for young plants
• Spring optimal timing
• Progressively larger containers
• Refresh alkaline medium

Winter Care

• Maintain above 15°C (59°F)
• Reduce watering by 40%
• No fertilization in winter
• Maximum available light
• Monitor for scale insects

7. Landscape and Outdoor Cultivation

Landscape Excellence

• Outstanding specimen palm
• Coastal gardens ideal
• Limestone soil perfect
• Wind tolerant
• Low maintenance

Design Uses

• Focal point palm
• Avenue plantings
• Beach landscapes
• Xeriscape appropriate
• Mediterranean gardens
• Poolside plantings

Site Selection

• Full sun preferred
• Well-draining soil essential
• Alkaline conditions beneficial
• Wind exposure tolerated
• Coastal locations ideal

8. Cold Climate Cultivation Strategies

Cold Hardiness

Moderate for a tropical palm but limited to frost-free areas.

Winter Protection

• Protection needed below 12°C
• Frost cloth for cold snaps
• Mulch heavily around base
• South exposure best

Hardiness Zone

• USDA 10a-11 standard cultivation
• Zone 9b with excellent protection
• Coastal areas have advantage
• Microclimate selection critical

Winter Protection Systems and Materials

For Marginal Areas

• Microclimate selection crucial
• Thermal mass nearby (rocks, water)
• Overhead protection from structures
• Wind barriers important

Establishment and Maintenance in Landscapes

Planting Techniques for Success

Site Preparation

• Full sun to light shade
• Well-draining soil crucial
• Add limestone if soil acidic
• Consider wind patterns

Planting Process

• Large hole with amendments
• Plant slightly high for drainage
• Stake if very windy location
• Water thoroughly after planting

Establishment

• Regular water first year
• Wind protection initially
• Begin feeding early
• Monitor growth and health

Long-term Maintenance Schedules

Overall: Minimal maintenance required. This palm is remarkably self-sufficient, disease resistant, drought tolerant, and maintains natural beauty with minimal intervention.