1. Introduction

Habitat and Distribution, Native Continent

Pritchardia schattaueri is one of the rarest palms in the world, endemic to the Island of Hawaiʻi (Big Island). The entire wild population is restricted to a single location on the southwestern slopes of South Kona, between 600-900 meters elevation. This critically endangered species grows on old pāhoehoe and ʻaʻā lava flows in mesic to dry forest remnants, where it receives 750-1,500mm of annual rainfall with a pronounced summer dry season. The habitat is characterized by well-drained volcanic soils, partial shade from remnant native trees like Diospyros sandwicensis (lama) and Metrosideros polymorpha (ʻōhiʻa), and protection from strong winds by topography. Named after George Schattauer, who discovered the population in 1977, fewer than 120 wild individuals remain.

Native range: South Kona, Big Island, Hawaiʻi
Single population • 600-900m elevation • Click markers for details

Taxonomic Classification and Scientific Classification

Synonyms

• No synonyms (recently described distinct species)
• Sometimes confused with P. affinis in older literature
• Occasionally mislabeled as P. beccariana

Common Names

• Schattauer's loulu (English)
• South Kona pritchardia (English)
• Loulu (Hawaiian - general term for Pritchardia)
• Hāwane (alternative Hawaiian)
• 夏塔尔椰子 (Chinese)

Expansion in the World

P. schattaueri remains extremely rare in cultivation:

• National Tropical Botanical Garden, Hawaii (conservation collection)
• Waimea Arboretum, Oahu (ex-situ preservation)
• Montgomery Botanical Center, Florida (few specimens)
• Private collections in Hawaii (limited)
• UC Botanical Garden, Berkeley (single specimen)
• IUCN Red List status: Critically Endangered

The extreme rarity in cultivation reflects the tiny wild population, difficulty in obtaining seeds, and specific growing requirements.

2. Biology and Physiology

Morphology

Trunk

P. schattaueri develops a solitary, robust trunk reaching 8-15 meters in height with a diameter of 25-35cm. The trunk is gray to brown, relatively smooth in younger specimens but becoming roughened with persistent leaf bases in older palms. Unlike some Pritchardia species, the trunk shows minimal swelling at the base. Distinctive horizontal leaf scars are prominently visible at 10-15cm intervals.

Leaves

The crown consists of 20-30 massive, costapalmate leaves forming a dense, spherical canopy. Individual leaves measure 1.5-2 meters across, nearly circular, divided to about one-third into 60-80 segments. Petioles are 1.5-2 meters long, unarmed, with a distinctive reddish-brown tomentum when young. The leaf blade is deep green above, paler below with a slight waxy coating. A distinguishing feature is the relatively stiff segments that resist wind damage better than many Pritchardia species.

Flower Systems

P. schattaueri is hermaphroditic with spectacular interfoliar inflorescences. The branched panicle emerges from among the leaves, reaching 1-1.5 meters in length. The inflorescence axis and branches are covered in dense brown tomentum. Flowers are small (3-4mm), pale yellow to cream, arranged in clusters along the rachillae. Each flower contains 6 stamens and a single pistil with three carpels. Flowering occurs primarily from March to June, with peak activity in April-May.

Life Cycle

P. schattaueri has an extended life cycle of 80-150 years:

• Germination to Seedling (0-5 years): Slow establishment phase
• Juvenile Phase (5-20 years): Trunk development begins
• Sub-adult Phase (20-40 years): Rapid vertical growth
• Adult Phase (40-120 years): Full reproductive maturity
• Senescent Phase (120-150 years): Gradual decline

First flowering typically occurs at 25-35 years when palms reach 5-7 meters height.

Specific Adaptations to Climate Conditions

• Drought Tolerance: Deep taproot for dry season survival
• Wind Resistance: Stiff leaf segments reduce damage
• Lava Rock Adaptation: Roots penetrate rock crevices
• Fire Recovery: Can resprout from base after crown damage
• Salt Spray Tolerance: Waxy leaf coating provides protection
• Slow Growth: Conservative strategy in nutrient-poor soils

3. Reproduction and Propagation

Seed Reproduction

Seed Morphology and Diversity

P. schattaueri produces globose to slightly ovoid fruits, 25-35mm in diameter, among the larger fruits in the Hawaiian Pritchardia. Immature fruits are green, ripening to brown or blackish-brown. The epicarp is thin and smooth; mesocarp is fibrous and dry at maturity; endocarp is thin and brittle. Seeds are globose, 18-25mm diameter, with homogeneous endosperm and a lateral embryo. Fresh seed weight ranges from 4-8 grams. The limited population shows concerning low genetic diversity.

Detailed Seed Collection and Viability Testing

Pre-germination Treatments

Step-by-step Germination Techniques

1. Medium: 50% perlite, 30% vermiculite, 20% coconut coir
2. Container: Deep pots (20cm+) or seed trays
3. Sowing: Plant 2-3cm deep
4. Temperature: Maintain 25-30°C (77-86°F)
5. Humidity: 70-80%
6. Light: Bright shade from emergence
7. Moisture: Keep evenly moist

Germination Difficulty

Moderate. Main challenges:

• Slow, irregular germination
• Temperature sensitivity
• Fungal problems in high humidity
• Rat predation if outdoors

Germination Time

• First emergence: 60-120 days
• Peak germination: 120-180 days
• Complete process: up to 300 days
• Success rate: 60-80% with fresh seeds

Seedling Care and Early Development

Year 1:

• Maintain stable conditions
• Begin fertilization at 6 months
• 60-70% shade required
• Growth very slow

Years 2-3:

• Increase container size
• Monthly fertilization
• Gradually reduce shade to 50%
• Watch for nutrient deficiencies

Years 4-5:

• Can plant outdoors in suitable climates
• Establish windbreak if needed
• Continue regular feeding

Advanced Germination Techniques

Hormonal Treatments for Germination Enhancement

4. Cultivation Requirements

Light Requirements

Species-specific Light Tolerance Ranges

• Seedlings (0-3 years): 300-800 μmol/m²/s (60-80% shade)
• Juveniles (3-10 years): 800-1500 μmol/m²/s (40-60% shade)
• Sub-adults (10-20 years): 1500-2000 μmol/m²/s (20-40% shade)
• Adults: Full sun to light shade (2000+ μmol/m²/s)

Gradually increase light exposure with age.

Seasonal Light Variations and Management

• Young plants need consistent shade
• Adults handle seasonal variations well
• Protect from intense afternoon sun when young
• Full sun tolerance develops slowly

Artificial Lighting for Indoor Cultivation

• High light requirements for growth
• Metal halide or LED recommended
• 14-16 hour photoperiod
• Minimum 400 foot-candles

Temperature and Humidity Management

Optimal Temperature Ranges

• Ideal: 20-28°C (68-82°F)
• Acceptable: 15-35°C (59-95°F)
• Minimum survival: 5°C (41°F)
• Maximum tolerance: 40°C (104°F)
• Handles temperature fluctuations well

Cold Tolerance Thresholds

• Light damage: Below 10°C (50°F)
• Severe damage: 5°C (41°F)
• Fatal: 0°C (32°F)
• Brief cold snaps tolerated by adults

Hardiness Zone Maps

• USDA Zones: 10a-12
• Marginal in Zone 9b with protection
• Sunset Zones: 19-24, H1-H2
• European hardiness: H2-H3

Humidity Requirements and Modification

• Optimal: 50-70%
• Minimum tolerable: 30%
• Adapts to lower humidity than most Pritchardia
• Benefits from occasional misting

Soil and Nutrition

Ideal Soil Composition and pH

Nutrient Requirements Through Growth Stages

Seedlings (0-3 years):

• Light feeding essential
• 3-1-2 ratio monthly
• Half strength initially

Juveniles (3-10 years):

• NPK ratio: 8-2-12+4Mg
• Monthly application
• Micronutrients important

Adults (10+ years):

• NPK ratio: 8-3-12
• Quarterly application
• Increase potassium for flowering

Organic vs. Synthetic Fertilization

Organic Program:

• Volcanic rock dust beneficial
• Composted mulch
• Bat guano supplements
• Slow-release approach

Synthetic Approach:

• Controlled-release palms special
• Supplements with minors
• Avoid high salt formulations
• Monitor for burn

Micronutrient Deficiencies and Corrections

• Magnesium: Common - Epsom salts quarterly
• Manganese: "Frizzletop" - manganese sulfate
• Iron: Yellowing - chelated iron
• Boron: Growing point problems - borax

Water Management

Irrigation Frequency and Methodology

• Moderate water requirements
• Deep, infrequent watering preferred
• Increase during growth season
• Reduce in winter

Drought Tolerance Assessment

• Good drought tolerance once established
• Survives on rainfall in suitable climates
• Young plants vulnerable
• Mulching helps retention

Water Quality Considerations

• Tolerates various water sources
• Moderate salt tolerance
• pH 6.0-8.0 acceptable
• Avoid reclaimed water

Drainage Requirements

• Excellent drainage mandatory
• No waterlogging tolerance
• Raised planting in clay soils
• Volcanic amendments help

5. Diseases and Pests

Common Problems in Growing

• Lethal yellowing: Not susceptible (major advantage)
• Scale insects: Occasional problem
• Rat damage: Serious threat to seeds/seedlings
• Nutrient deficiencies: In poor soils

Identification of Diseases and Pests

Disease Issues:

• Phytophthora root rot: In waterlogged soils
• Ganoderma butt rot: In older specimens
• Leaf spots: Various fungi in high humidity
• Generally disease-resistant

Pest Problems:

• Coconut rhinoceros beetle: Emerging threat
• Palm weevils: Bore into trunk
• Scale insects: On leaves and petioles
• Rats: Major seed predators

Environmental and Chemical Protection Methods

Cultural Prevention:

• Proper drainage prevents root rots
• Good nutrition prevents deficiencies
• Physical barriers against rats
• Regular monitoring essential

Chemical Controls:

• Systemic insecticides for borers
• Fungicides rarely needed
• Rat bait stations
• Minimal pesticide approach preferred

6. Indoor Palm Growing

Specific Care in Housing Conditions

Indoor Challenges:

• High light requirements
• Large ultimate size
• Low humidity tolerance helps
• Spectacular specimen potential

Container Limitations:

• Needs very large containers
• Heavy when mature
• Root restriction affects growth
• Annual repotting when young

Success Factors:

• Maximum light exposure
• Good air circulation
• Regular feeding program
• Consistent temperatures

Replanting and Wintering

Replanting Schedule:

• Annually when young
• Every 2-3 years when mature
• Spring timing optimal
• Pot-bound plants flower better

Replanting Process:

1. Water day before
2. Choose pot 20% larger
3. Use fresh volcanic mix
4. Maintain same depth
5. Stake if needed

Winter Care:

• Maintain above 15°C (59°F)
• Reduce watering 30-50%
• No fertilization December-February
• Maximum light exposure
• Watch for spider mites
• Good air circulation

7. Landscape and Outdoor Cultivation

Landscape Value

• Specimen palm supreme
• Hawaiian garden essential
• Conservation value high
• Architectural presence

Design Applications

• Focal point planting
• Avenue possibilities
• Coastal gardens (with protection)
• Xeriscape appropriate

8. Cold Climate Cultivation Strategies

Cold Hardiness

Moderate cold tolerance for a Hawaiian endemic.

Winter Protection

• Hardy to brief 5°C (41°F)
• Protect below 10°C (50°F) when young
• Overhead protection beneficial
• Mulch heavily in marginal areas

Hardiness Zone

• USDA 10a-12 standard
• Zone 9b possible with microclimate
• Mediterranean climates suitable

Winter Protection Systems and Materials

Marginal Climate Success:

• Plant near thermal mass
• Overhead canopy for frost
• Wrap trunk when young
• Ensure perfect drainage

Emergency Protection:

• Frost blankets ready
• Christmas lights for heat
• Anti-desiccant sprays
• Monitor forecasts closely

Establishment and Maintenance in Landscapes

Planting Techniques for Success

Site Selection:

• Full sun to partial shade
• Protection from strong winds
• Well-draining location
• Allow for eventual size

Soil Preparation:

• Deeply cultivate
• Amend with volcanic material
• Ensure drainage
• Add mycorrhizae

Planting Process:

1. Plant at same depth as container
2. Water deeply
3. Mulch immediately
4. Stake if windy location

Long-term Maintenance Schedules

Monthly (Growing Season):

• Deep watering if dry
• Fertilizer application
• Pest monitoring

Quarterly:

• Comprehensive health check
• Prune dead fronds only
• Adjust nutrition program

Annually:

• Soil testing
• Mulch renewal
• Support system check
• Photo documentation

Special Conservation Notes:

• Document growth rates
• Collect and share seeds
• Report to conservation groups
• Maintain genetic records